5 Dictionaries: Use and Evaluation

C M Anand

I. Objectives

After studying this module the learner will be able to:

define a dictionary,
know the historical development of dictionaries,
identify different types of dictionaries,
state the differences between comprehensive unabridged dictionaries with abridged, desk or pocket dictionaries,
know the difference between print, electronic and online dictionaries, and evaluate different types of dictionaries.

II. Learning Outcome

After studying this module the learner will be able to define a dictionary, know the historical development of dictionaries and identify different types of dictionaries. You will also be able to state the differences between comprehensive unabridged dictionaries with abridged, desk or pocket dictionaries. You will know the difference between print, electronic and online dictionaries, and lastly, you will be capable of evaluating different types of dictionaries.

From the usage point of view there are dictionaries for adults, young adults and children. Based on the physical format, the dictionary can be in print, electronic form or accessible online. There are hundreds of dictionaries, to select the most suitable one for a library or even for individual use it should evaluated.

III. Module Structure

Introduction
History
Types of Dictionaries
1. General Language Dictionaries
2. Subject Dictionaries
3. Special Dictionaries
4. Translating Dictionaries
Online and Electronic Dictionaries
Uses of Dictionaries
Evaluation of Dictionaries
1. Authority
2. Vocabulary
3. Treatment of Words
4. Continuous Revision
5. Standards and Usage
6. Special Features
7. Spelling
8. Grammatical Information
9. Format
10. Evaluation of Online and Electronic Dictionaries
Summary
References

1. Introduction

Dictionaries are among the most commonly used reference books. A dictionary consists of alphabetical list of words with their meaning, definition, etymology, pronunciation and usage. Dictionaries give meaning of many kinds of words. Most general language dictionaries include the ordinary words of everyday life; literary words used in formal writing; words not used today, but found in writings of some authors; idioms; abbreviations; important persons as well as place names and words and phrases from other languages.

A dictionary can be defined as ‘A book containing words of a language arranged in alphabetical order with explanation of their meanings (Noah Webster).

Most dictionaries describe the facts of a language as educated speakers and writers use it. These dictionaries are called ‘Descriptive Dictionaries’, because the editor does not change the facts of a language. However, many older dictionaries tried to prescribe rules for the usage of words, these dictionaries are called ‘Prescriptive Dictionaries’.

The other reference book which deals with words is a Thesaurus. Thesaurus is a book in which words that have the same or similar meaning (synonyms and sometimes antonyms) are grouped together. Dictionary helps to find meaning and pronunciation of the words. Thesaurus helps to find most appropriate word to express an idea and also other related words, e.g. Roget’s Thesaurus.

Glossary is an alphabetical list of words related to a specific subject, text or dialect, with explanation. A glossary is usually provided at the back of the book showing the definitions of technical terms used in that book.

2. History

The word dictionary comes from Medieval Latin word ‘dictionarium’, which in turn comes from the Latin ‘dictio’, meaning word or saying. The ancient Greeks and Romans were the first to produce these works. But most Greek and Latin dictionaries were either lists of rare or difficult words or specialized lists of words. Towards the end of Middle Ages, English, French, German and other national languages of Europe developed and Latin was no longer in use. As these languages became accepted in each country, people needed new dictionaries to explain the hard words of their own language in terms of simpler words in the same language. In 1604, Robert Cowdrey prepared an English dictionary, called The Table Alphabeticall of Hard Words. It defined about 3000 English words that had been taken from other languages. The first general and comprehensive dictionary of English language was Universal Etymological English Dictionary by Nathan Bailey published in 1721. Thisdictionary listed 60,000 words. This was the first English dictionary that tried to include most English words instead of hard words only.

In early 1700s, several literary men of England wanted to prepare a dictionary that would set standard for good usage in English. French and Italian scholars had already published such prescriptive dictionaries in their languages, and this success influenced the literary men of England. Samuel Johnson undertook the task of preparing an English language dictionary. He spent several years selecting quotations from the best writers to illustrate the meanings of words. Samuel Johnson published his great work, A Dictionary of English Language in 1755. There were many quotations in the dictionary to illustrate the use of words and these illustrative quotations have been repeated by makers of dictionaries since that time. Johnson’s dictionary was used in England and America until 1828, when it was superseded by Noah Webster’s American Dictionary of the English Language. Webster’s Third New International Dictionary of the English Language is the successor to 1828 work. Since then Webster’s dictionary is frequently revised and is widely used.

Another important scholarly English language dictionary was A New English Dictionary on Historical Principles. It appeared in parts from 1884 to 1928 and had about 415,000 entries. In 1933, it was published in 12 volumes with one-volume supplement, as the Oxford English Dictionary (OED). The dictionary gives a historical record of each meaning of a word and tells the date the word first occurred in written English. It also lists other dates that show how the word has been used through the years. No other dictionary in any language approaches the OED in wealth and authority of historical detail. A four volume supplement was published from 1972 to 1985 and a fully revised edition in 20 volumes appeared in 1989. Since then OED is frequently revised and is widely used today.

3. Types of Dictionaries

Based on the number of words, scope and coverage of other items of information, the dictionaries can be categorized into following groups:

• General Language Dictionaries;

• Subject Dictionaries;

• Special Dictionaries; and

• Translating Dictionaries

General Language Dictionaries can be further categorized based on purpose, size and target user group as follows:

According to size:

• Unabridged Dictionary

• Abridged, Desk or College Dictionary

• Pocket Dictionary

According to target user group:

• Adults

• Young Adults

• Children

According to purpose:

• Prescriptive

• Descriptive

3.1 General Language Dictionaries

General language dictionaries cover all the words of a language and give meanings, definition, and explanation of the words in the same language. The language may be English, French, Hindi, German or Russian. For instance, English language dictionaries will include English words and give their meanings in English language. These dictionaries are also called monolingual dictionaries. These dictionaries include information on commonly used words of a language as well as scientific, technical, and other subject terms. General language dictionaries can further be divided according to size, volume and the target user group. Comprehensive /Unabridged general dictionaries contain more than 250,000 words. These dictionaries try to cover all the words of a language, including past as well as currently in use words. Abridged/College dictionaries contain 130,000 to 180,000 words. Desk and children’s dictionaries contain 40,000 to 80,000 words.

Abridged/College dictionaries cover most common and currently used words. Children dictionaries cover words related to the course curriculum. The meanings and definitions are written in simple language which children can comprehend. Children dictionaries also include more illustrations to make children understand the concept.

Most of the reputed publishers of unabridged standard general language dictionaries bring out abridged, desk, college, and children editions of their dictionaries. Publishers of these dictionaries try to do continuous revision with each new printing they add or delete a given number of words. This is particularly true for desk dictionaries which are used by young people and must reflect current usage and new words introduced into the language via radio, television, music, technology and like.

Following are some examples of standard general language dictionaries :

Merriam-Webster’s Third New International Dictionary of the English Language. The print edition of the dictionary is in 3 volumes. It was published in 1961 by G&C Merriam. Latest revision came in Mar. 6, 2013 under the name The New Merriam-Webster Unabridged Dictionary. The Dictionary has over 476,000 entries. It has special updated Addenda Section of new words and meanings, 3000 illustrations and 140,000 etymologies describing word origins.

Online version of this dictionary is Merriam–Webster Unabridged–Online Dictionary. This dictionary is subscription based dictionary with 470,000 Entries and 700,000 definitions,

143,000 Etymologies, 100,000 Quotations, 107,000 Verbal illustrations, and 3,100 Pictorial illustrations. In addition the dictionary provides access to Webster’s Collegiate Dictionary and Thesaurus and Medical Spanish-English & French—English Dictionary. (http://unabridged.merriam-webster.com)

Merriam-Webster’s Collegiate Dictionary: The 11th Edition, published in 2003 includes 165,000 entries and over 225,000 definitions.

Merriam-Webster’s School Dictionary includes more than 100,000 words, nearly 1,000 illustrations and about 1500 usage examples.

Oxford English Dictionary (OED): Second Edition of the dictionary is in 20 volumes. This dictionary is not a dictionary for ready reference. It is encyclopaedic in nature in treatment of words. Under each word anything that can be found about the historical development of the word is traced in chronological order. Meaning, origin, relation to similar other words, various dialects, fashions in speaking, pronunciation, compounds, derivatives are traced and every change is illustrated by an example and each quotation is dated and source is indicated. The dictionary includes 600,000 words. History of the word and of the language is traced through 3 million quotations. Second edition of the dictionary is available in 20 volumes in print or as single volume as compact edition. Three volume addition series is also available in print.

Oxford English Dictionary- Online: This version is authoritative guide to the meaning, history, and pronunciation of over 600,000 words -past and present- from across the English speaking world. Online version is updated every three months. (http://www.oed.com/about).

Concise Oxford English Dictionary, (Book and CD-ROM) 12th edition covers over 240,000 entries and has 1682 pages. It covers all words, phrases and meanings that form central vocabulary of English language in the modern world. Special attention has been given to scientific and technical vocabulary. The print edition is available with CD-ROM, which includes over 50,000 spoken audio pronunciations.

Oxford University Press has wide range of dictionaries for college students to school children. There are learner’s dictionaries too for non-English speaking people. Words included in students and children’s dictionaries are related to what they are learning at school, the books they read at various levels from primary to high school and above. Children’s dictionaries have more illustrations to explain the concept. Some examples of these dictionaries from Oxford University Press are as follows:

Oxford Primary Dictionary for Age group 7-10 years has over 30,000 words and phrases.

Oxford Illustrated Children’s Dictionary for Age group 8-10 years has over 50,000 words and definition, with special focus on school subject vocabulary including English, Mathematics and Science to help with home work.

Oxford English Dictionary for Schools for Age group 11-16 years has over 50,000 words and phrases with examples from best children’s books to see usage, as well as word families, synonyms and spelling notes.

Oxford Students Dictionary for intermediate to advance level includes over 52,000 words and phrases and their meanings in British and American English with curricula words highlighted. It has 40 reference pages to support academic writing and improve study skill. It has over 200 diagrams and illustrations to help students understand scientific and technical aspects.

Oxford Essential Dictionary for learners of English language. The dictionary helps learners to learn the words they need to know and how to use them. It covers 19,000 British and American headwords with 13,000 examples. The Dictionary has 16 study pages to cover skills such as telephoning, letter writing and everyday conversation. The CD-ROM version of the dictionary has speaking dictionary with record and playback facility. It has picture dictionary with illustrations and 66 video clips. One can view a free online demonstration of CD-ROM version of the dictionary. (http://www.oxforddictionaries.com).

Oxford Advanced Learner’s Dictionary, 8th Edition for students and adult learners of English. The dictionary has 184,000 words, phrases and meanings. The most important meaning of about 3000 words is marked with key symbol. It has 32-page writing tutor on CD-ROM with tips and guidance on tackling different types of writing. The dictionary has 64-page colour visual vocabulary builder.

Oxford University Press (OUP) is the leading publisher of English Language Teaching (ELT) materials for Indian schools. Specifically designed to meet needs of English learners, OUP India (http://www.oup.co.in) has also provided electronic teaching support in the form of CDs and through Web. The website, “Learning to Communicate” (http://www.oupnltc.com) is recently launched website for school education.

World Book Dictionary: Published by World Book Inc., it is a two-volume English dictionary, published as supplement to World Book Encyclopaedia. The dictionary includes 225,000 terms and provides information about meaning, spelling, and pronunciation of most important and frequently used words. It has over 3000 illustrations. Since, the dictionary is especially designed for use with World Book Encyclopaedia, biographical and geographical information is not included. The dictionary includes 124 pages of educational material on vocabulary development and information on how to write effectively.

World Book Student Dictionary for students from grade 2 to grade 8 covers curriculum related words and helpful illustrations to clarify the meaning. Words are defined in simple manner for better comprehension.

3.2 Subject Dictionaries

General language dictionaries, even comprehensive ones, find it difficult to cover all words of specialized nature and more and more such words are coined every day. Subject dictionaries concentrate on the definition of the words in a given subject. Subject dictionaries are becoming increasingly common, due to increase in study and research in different subject areas ranging from arts, humanities, social sciences to science and technology. Some of the examples of subject dictionaries are as follows:

McGraw Hill Dictionary of Scientific and Technical Terms, 6th Edition, is a comprehensive dictionary of scientific and technical terms covering over 115,000 terms and 125,000 definitions in 104 areas of science and technology. Each term is defined in clear and simple language, understandable to general reader. Pronunciation key and the subject category of each term are given. There are over 3000 black and white illustrations. The dictionary also contains 35-page table of elements, important biographical listings and 12 more sections of scientific information.

Oxford University Press also brings out wide range of subject dictionaries for students such as Oxford Dictionary of Astronomy, Oxford Dictionary of Chemistry, Oxford Dictionary of Biology etc.

3.3 Special Dictionaries

The dictionaries which are compiled for special purpose or which deal with linguistic aspect of the words (such as pronunciation, synonym and antonyms etc.) or literary aspect of the words (such as quotations, idioms, proverbs etc.) or with special type or class of words (such as obsolete words, abbreviations and acronyms etc.) are called special dictionaries. Though most of these aspects of the words are covered by general language dictionaries as well, but special dictionaries cover these aspects much more comprehensively. Special dictionaries supplement general language dictionaries. Some of the examples of special dictionaries are as follows:

Cambridge English Pronouncing Dictionary – 17th edition from Cambridge University Press on CD-ROM. The dictionary provides spoken British and American pronunciation for every word. Cambridge dictionary is also available for mobile phones.

Cambridge Idioms Dictionary – 2nd Edition from Cambridge University Press. The dictionary explains the meaning and use of over 7000 idioms in British, American and Australian English.

Cambridge Phrasal Verb Dictionary is available online along with many other titles from Cambridge dictionaries. Using Cambridge Dictionary Application, one can download any Cambridge dictionary on mobile phone as well.

The Oxford Dictionary of Quotations – 7th edition published in 2009 lists short quotations that are common in English language and culture.

3.4 Translating Dictionaries

Translating dictionaries give meaning of the word from one language to another. These dictionaries are either bilingual or multilingual. The bilingual dictionaries give meaning of a word from one language to another language. For example, an English-Hindi dictionary, will list words in English and give equivalent words in Hindi. A multilingual dictionary gives meaning of a word in more than two languages. These dictionaries normally do not define the words, but translate the words from one language to another language. Many of them are limited in scope to certain fields such as astronomy, biology, electronic, etc. Bilingual dictionaries can be unidirectional, meaning that they list the meanings of the words of one language to another. They can be bidirectional, providing translation to and from both the languages. Bidirectional bilingual dictionaries usually consist of two sections, each listing words and phrases of one language alphabetically along with their translation. These dictionaries are used by translators, linguistics, language students and all those who are interested in foreign language.

Examples of bilingual and multilingual dictionaries:

Concise Oxford Spanish Dictionary, 4th edition published in 2009, is comprehensive English- Spanish and Spanish-English dictionary with 175,000 words and phrases and over 200,000 translations. The online edition of this dictionary covers 300,000 words and phrases and 500,000 translations.

Oxford Russian Dictionary, 4th edition, published in 2007, has over 500,000 words and phrases and translations. The dictionary is also available online.

Multilingual Biomedical Technical Dictionary: (in English, Spanish, Portuguese, French, German, Swedish and Dutch). The dictionary covers over 40,000 entries with about 40,000 synonyms and details each in English, French, Swedish, Portuguese, Spanish, Dutch and German.

Oxford English-English-Hindi Dictionary, It is a comprehensive and authoritative dictionary compiled for learners of English, teachers, translators and general readers. The dictionary has 50,000 entries covering phrases, idioms, S&T terms, and words relevant to Indian subcontinent. It provides detailed meanings of synonyms in English and Hindi. It also includes detailed notes on English grammar, vocabulary and usage.

Shabdkosh- English-Hindi Dictionary (http://www.shabdkosh.com) the site provides English to Hindi as well as Hindi to English translation. The site was conceptualized and designed by ManeeshSoni, a graduate from Indian Institute of Technology, New Delhi in 2003 with about 15,000 words from public domain dictionary compiled by Ram NarainLal. The dictionary has over tens of thousands of words.

Many sites offer free translation facility on the Web. Listed below are some of these sites:

• http://www.bablfish.yahoo.co/

• http://www.freetranslation.com/

• http://www.systran.com/

• http://www.babylon.com/

4. Online and Electronic Dictionaries

An online dictionary is a dictionary that is accessible via Internet through a web browser. These dictionaries are available on the Internet either free or free with a paid subscription for extended or more professional content. Some premium dictionaries, such as Oxford English Dictionary Online, are available only on subscription basis. Some of the examples of free online dictionaries are: The Free Dictionary.com (http://www.thefreedictionary.com), Dictionary.com (http://www.dictionary.com), and Merriam-Webster’s Learner’s Dictionary (http://www.learnersdictinary.com).

Electronic dictionary is a dictionary whose data exists in digital form and can be accessed through a number of devices such as, a dedicated hand-held device or as an application on smart phones and tablet computers or computer software as a function build into an E-Reader, or as CD-ROMs and DVD-ROMs, packaged with printed dictionary, to be installed on the user’s own computer, as free or paid for online products. Most of the early electronic dictionaries were print dictionaries, made available in digital form. The contents were identical, but editors provided users with more powerful search functions. Electronic dictionaries have additional advantages over their print counter parts, they can incorporate more number of words and have provision of including multimedia contents, such as audio pronunciation and video clips.

5. Uses of Dictionaries

General language dictionaries are used to find meanings and spelling of the words, their pronunciation, form of words, capitalization, etymology, word division and contextual usage. Considering the range of dictionaries available, the dictionaries can be used in finding synonyms, homonyms, framing sentences, increasing vocabulary, writing essays and speaking English more fluently. Dictionaries also serve as a language recorder. Some prescriptive dictionaries set standard for spoken and written English language.

Similarly, special dictionaries dealing with special aspect of the language, such as literary aspect of the words, help in finding suitable proverb, idioms, phrases and foreign terms. Dictionaries dealing with special class of words such as obsolete words, abbreviations, Acronyms etc. are helpful in finding the full form of abbreviations, acronyms, etc. There is wide range of special dictionaries, compiled for particular class of people. For example there are rhyming dictionaries, which are meant for poets.

Bilingual and multilingual dictionaries are useful in translating works of a specific subject from one language to the other. Such dictionaries are useful for translators for translating scientific and technical articles, novels, poems, technical manuals etc. These dictionaries are also useful for the travellers who are not familiar with the language of the country they intent to visit.

6. Evaluation of Dictionaries

There can be no single perfect dictionary at any given point of time, as language is constantly evolving, adopting new words in written and spoken language as well as words emerging through new discoveries in science and technology, which dictionaries have to constantly incorporate to keep them up-to-date. Dictionaries also have to drop words which are no longer in use in any language. When a library has to purchase dictionaries, it has to select from the range of dictionaries available in the market and select the ones that are most suitable for the target users of the library. The best sources for evaluation of dictionaries are Kenneth Kister’s Dictionaries Buying Guide and Kister’s Best Dictionaries for Adults and Young Adults.

However, there are certain set of evaluation criteria for assessing the usefulness of dictionaries and these should be taken into consideration while purchasing a dictionary. Criteria for evaluation of dictionaries are as follows:

6.1 Authority

Authority and reputation of the lexicographer and publisher should be evaluated. For example, in the unabridged English dictionaries field there are three major publishers Merriam-Webster, Oxford University Press and Random House Incorporation, and they are recognized for lexical authority. The same publishers issue abridged, college, desk, pocket and children dictionaries. But there are number of reputable firms which publish abridged dictionaries, such as Houghten Mifflin (Illustrated Heritage Dictionary), World Publishing Company (Webster 20th Century Dictionary) and World Book Inc. (World Book Dictionary.

6.2 Vocabulary

Vocabulary may be considered in terms of period of language covered and number of words or entries in the dictionary. Unabridged dictionaries have entries between 300,000 to 600,000 and abridged dictionaries have entries ranging from 50,000 to 200,000. The scope and purpose of the dictionary can be assessed by going through its preface and introduction. The type of readers for whom it is compiled, helps us to know the purpose of the dictionary.

6.3 Treatment of Words

Regardless of price, number of entries or any other consideration a dictionary must indicate spelling, meaning, pronunciation and syllabication of a word. Preferably in single alphabet it should indicate etymology, major place names with clear indication whether the entry represent a place, river or mountain or any other item; major personal names from history, mythology; foreign terms; phrases; synonyms and antonyms; abbreviations and general slang terms clearly marked.

6.4 Continuous Revision

Publishers of dictionaries try to do continuous revision. All the reputable dictionary publishers, particularly those of college and desk dictionaries update their work thoroughly every 3 to 4 years and often make minor revision with each printing. With each new printing they may add or delete a given number of words. This is more common in desk dictionaries, which are mostly used by young people and must reflect current usage and new words introduced in the language via radio, television, music, technology etc. The task of revision has become easy now because of the availability of database of words of the dictionaries in computerized form. While evaluating a dictionary, one must check about the revision policy of the publication.

6.5 Standards and Usage

Today most of the modern dictionaries are descriptive rather than prescriptive. Descriptive dictionaries describe the language. They include words that are commonly used even if they are non-standard. Editors are of the opinion that people dictate the proper use of a language. Hence while illustrating definition of a word in modern dictionary, it is important to use quotes not only from literature, but from newspapers, television programmes and speeches. Although, earlier dictionaries prescribed rules for correct usage of words, modern editors broke away from the tradition. Prescriptive dictionaries tend to be more concerned about correct or standard English. They prescribe the proper usage and spelling of words. There are some dictionaries which provide guides to correct usage of words. Three such dictionaries are: The American Heritage Dictionary with extensive usage notes; Harper Dictionary of Contemporary Usage and Fowler’s Dictionary of Modern English Usage.

6.6 Special Features

In addition to the above, one must check what special features the dictionary is offering, such as illustrations, geographical and historical details of places, biographical information, tables of weights and measures, almanac type of material, abbreviations and acronyms, foreign terms, word and phrases used in various subjects etc.

6.7 Spelling

Another important thing to notice is the spelling. Variant form of spelling of a word should be clearly indicated by providing label ‘British’ or ‘American’ as the case may be. Words like ‘Color’ or ‘Colour’, ‘Organisaton’ or ‘Organization’, etc. require such clarification.

6.8 Grammatical Information

The most generally useful help a dictionary offers is to indicate parts of speech. All single entries are classified as nouns, adjectives, or verbs. Apart from this major division, dictionaries may vary in method of showing adverbs, adjectives, plurals and principle parts of a verb, particularly past tense of irregular verbs.

6.9 Format

In evaluating format of a dictionary, the important aspects to consider are, the clear printing, print size of the words and how the readability is affected by spaces between the words; the use of boldface type; adequate margin on both the side and thumb indexes for each alphabet. With the exception of some coloured plates, in most dictionaries, the illustrations are in black and white line drawing. The average desk dictionary has 600-1500 illustrations; the unabridged has 700-12000 illustrations. Children dictionaries often have more illustrations than other dictionaries in order to clarify the concept. Where appropriate, actual size of the object illustrated should be indicated, particularly in the case of an animal or plant. The dictionary should be hard- bound and over-all appearance should be appealing.

6.10 Evaluation of Online and Electronic Dictionaries

Electronic and online dictionaries should be evaluated on the basis of quality of hardware (handheld devices), software (presentation and performance), and the information contents of the dictionary. Hand held device should be robust with good keyboard or touch screen system. The information on the GUI of computer based software should be clear, easy-to-use, with good font- size and pleasing colour. As far as the contents are concerned, the dictionary should include all the lexical information, which is expected from a quality printed dictionary. The dictionaries intended for collegiate and professional users, generally include most or all the lexical information. The content of electronic dictionaries developed in association with leading publishers of printed dictionaries, is more reliable than those aimed at travellers or casual users.

7. Summary

A dictionary can be defined as a book containing words of a language arranged in alphabetical order with explanation of their meaning. Dictionary is one of the most extensively used reference source by the people. Based on the treatment of words, dictionaries can be categorized as general language dictionary, subject dictionary, special dictionary and bilingual or multilingual dictionary. Based on the size and number of words covered, general language may be most comprehensive unabridged dictionary, abridged college or desk dictionary, or small pocket dictionary. From the usage point of view there are dictionaries for adults, young adults and children. Based on the physical format, the dictionary can be in print, electronic form or accessible online. There are hundreds of dictionaries, to select the most suitable one for a library or even for individual use it should evaluated. A dictionary needs to be evaluated when it is being purchased for a library or even for individual use.

8. References

Cassel, K A. Reference and Information Services in 21st Century- An Introduction. London: Facet Publication: 2006
Katz, W.A. Introduction to Reference W8th edition. New York. McGraw-Hill. 2vol. 2002.
Kenneth Krister’s Dictionary Buying G New York: R. R. Bowker Company. 1977.
Kister’s Best Dictionaries for Adults and Young People: A Comparative G Phoenix: The Oryx Press. 1992.
Krishan Kum Reference Service.5th edition. New Delhi. Vikas Publishing House Pvt. Ltd: 1995.