Reference Sources: A reference work / book / source is a compendium of information, usually of a specific type, compiled in a book for easy consultation. The entries are disjointed but arranged in such a way that the intended information can be quickly found when needed or referred to, the sequence of which is determined by the scheme of arrangement chosen for that purpose. It might be alphabetical, classified or some other type of arrangement. Even then the connection between consecutive entries is not as compelling and continuous or as free from jerks as between the paragraphs in an ordinary book. The writing style used in these works is informative; the authors avoid use of the first person and emphasize facts. Indexes are commonly provided in many types of reference work. Updated editions are published as needed, in some cases annually. Sometimes reference sources are also described as approach material. Broadly speaking, any book can be called a reference book provided the information contained in it is so organized that it becomes readily accessible. It may consist mostly of formulae, statistics, diagram, tables, maps, charts or list of documents with or without abstracts or annotations or other features. All reference sources are also documentary sources of information.
According to ALA Glossary, a reference book has been defined as “a book designed by its arrangement and treatment to be consulted for definite item of information rather than to be read consecutively”. Most of the reference book anticipates a particular need and approach to information.
Generally a reference source bears the following characteristics
i) Consulted for Definite Item of Information: They are not meant for continuous i.e. cover to cover reading. They are consulted from time to time (occasional) for particular pieces of information.
ii) Miscellany of Information: It is miscellany of information or facts and consists of disjointed entries of varying length which are collected from a vast number of sources. One entry in sources may or may not have any relationship with the other entry.
iii) Bird’s Eye View of the Topic: The books provide only the bird’s eye view of the topics and rarely deal with them in depth.
iv) Item can be Randomly Located: The arrangement of information is such that it can be conveniently and quickly recalled.
In the library, reference collections are shelved together in a special location separately from circulating items. Ordinarily, the reference collections are not lent out (circulated) or checked out from the library because they contain brief information about the topic in hand and, if needed, can be photocopied and, therefore, do not need to be borrowed by the users. Its availability in the library assures the provision of making it accessible on demand to any user to answer questions immediately. Reference books are also too valuable to permit the borrowers to take them out.
It may be added that the boarder line of demarcation between a reference book and others is not always sharp. The decision as to whether or not to regard a given book as a reference book will some time differ from library to library.
1. Classification of Reference Sources: William A. Katz divides the reference sources into two large categories-
i) Control Access Directional Type: It itself does not contain the required information but directs the user to the documents which contain the information. It includes bibliographies, catalogue, indexes, abstracts etc.
ii) Work of Sources Type: It itself contains the information. For example, Encyclopedia, Dictionary etc.
2. Types of Reference Sources: We may generally recognize the following kinds of reference sources based on the internal characteristics.
a) Dictionary: A dictionary contains the words of a language or the terms of a subject, profession or vocation arranged according to some definite order usually alphabetical, giving their meanings, pronunciation, spelling, significance and use. Some times synonyms, antonyms, derivation and history of the words or terms are also given. Many dictionaries also provide grammatical information, etymologies (origin and development of the4 meaning of the word), usage guidance and examples in phrases or sentences. The word "dictionary" comes from neoclassical Latin word “diccio” meaning simply "word". Therefore, primarily it deals with words and it is produced by lexicographers. A pictorial dictionary includes illustrations of the objects represented by the words listed; some other types of dictionary may also list out characters with their glyphs, or an alphabetical list of words with corresponding words in other languages. It is most commonly found in the form of a book. However, in recent years some dictionaries are also found in electronic portable handheld devices. Some examples of English language dictionaries are Merriam-Webster Dictionary, Oxford English Dictionary (descriptive), The American Heritage Dictionary of the English Language, Webster's Third New International Dictionary (descriptive).
i) Lexicon: A dictionary of some ancient language that generally provides more grammatical analysis is known as lexicon.
ii) Concordance: A concordance is an alphabetical list of the principal words used in a book or body of work showing location in the text with immediate contexts. Because of the time and difficulty and expense involved in creating a concordance in the pre-computer era, only works of special importance, such as the Bible, Qur'an or the works of Shakespeare, had concordances prepared for them.
iii) Glossary: A list of difficult terms along with some explanation or definition in a special field. The glossary is sometimes also referred to as word book.
b) Thesaurus: It is designed for drawing distinctions between similar words and assisting in choosing exactly the right word. So entries in a thesaurus should not be taken as a list of synonyms and antonyms. It also does not define words. That work is left to the dictionary. A formal definition of a thesaurus designed for indexing is: a list of every important term (single-word or multi-word) in a given domain of knowledge arranged in a systematic order and manifesting various types of relationship existing between the terms; and a set of related terms for each term in the list. The word “thesaurus” more commonly means a listing of words with similar, related, or opposite meanings (this new meaning of thesaurus dates back to Roget's Thesaurus). For example, a book of jargon for a specialized field; or more technically a list of subject headings and cross-references used in the filing and retrieval of documents (or indeed papers, certificates, letters, cards, records, texts, files, articles, essays and perhaps even manuscripts), film, sound recordings, machine-readable media, etc. Some examples of thesaurus are Thesaurus of English Words & Phrases (ed. P. Roget); The Synonym Finder (ed. J. I. Rodale); Webster's New World Thesaurus (ed. C. Laird); etc.
c) Encyclopaedia: The word encyclopaedia or encyclopaedia is derived from two Greek words ‘Enkyklios’ which means ‘circle’ and ‘Paideia’ which means “of learning”. The word encyclopaedia itself is synonymous with cyclopedia which means compendium of information or knowledge or a circle of knowledge, a work which represents synthesis of knowledge. It contains comprehensive written information on all branches of knowledge or a particular branch of knowledge, with the entries arranged in alphabetical order. Multi-volume encyclopedias often include an index in the last volume.
The Oxford English dictionary has defined an encyclopaedia as “a literary work containing extensive information on all branches of knowledge usually arranged in alphabetical order”. ALA Glossary of Library Terms define encyclopaedia as “a work containing information articles on subject in every field of knowledge usually arranged in alphabetical order or a similar work limited to a special field of subject”.
Four major characteristics of an encyclopaedia are its subject matter, its scope, its method of organization, and its method of production. It attempts to bring some order to the knowledge reflecting the state of knowledge as it exists during the period of its compilation. The included knowledge is related to kind of readership which an encyclopedia intends to serve. There have historically been two main methods of organizing printed encyclopedias: the alphabetical method (consisting of a number of separate articles, organized in alphabetical order), or organization by hierarchical categories. The former method is the most common by far, especially for general works. The encyclopedias are written by a number of employed text writers, usually people with an academic degree but some modern encyclopedia’s articles are collaboratively written by the experts on the subject.
The fluidity of electronic media, however, allows new possibilities for multiple methods of organization of the same content in the encyclopedias. Further, electronic media offer previously unimaginable capabilities for search, indexing, and cross reference.
Encyclopaedias can be general, containing articles on important topics in every field that describe the total accumulated knowledge on each topic or all that came before them. The general encyclopedias are larger compendia and often contain guides on how to do a variety of things, as well as embedded dictionaries and gazetteers. Every general encyclopaedic work is, of course, an abridged version of all knowledge discussed in depth However, the discussion of the included topic represents the opinions and worldviews of a particular time and the target audience is kept in view while discussing the topics. For example, New Encyclopædia Britannica, Encyclopedia Americana, Collier’s encyclopaedia, and German Brockhaus. The encyclopaedia can also specialize in a particular field such as an encyclopedia of medicine, philosophy, or law, Encyclopaedia of library and information science, International encyclopaedia of social sciences, McGraw Hill encyclopaedia of science and technology, etc.
i) Supplement to Encyclopedia: It is an annual or periodical publication issued by the publisher of the encyclopaedia. The purpose of encyclopedia supplement is to provide up-to-date information about the articles in the basic set and to bring out a summary of the major events, which have taken place during a year. But in reality it only serves as general reading and browsing and for summarizing the significant events. It is extremely useful to determine the trend of development in a particular field during the previous year. Examples: Britannica Book of the Year, Americana Annual, etc.
d) Bibliographical Sources: The term “bibliography” was first used by Louis Jacod de Saint Charles in his Bibliographia Parisiana. It is a technique of systematically producing descriptive list of written or published records or in simple writing and transcription of books. A bibliography is a systematic listing of the records of human communication. In its most general sense it is the study and description of books or other multimedia material. Bibliographical works are almost always considered tertiary sources of information. They differ from library catalogues by including all relevant publications rather than the items actually found in a particular library. However, the catalogues of some national libraries also serve as national bibliographies, as they contain almost all the publications of the concerned country. Standard citation formats are used in writing the bibliographies. The main advantages of bibliographic entries are that they contain enough information for readers to locate the materials and are presented in a consistent format. In many cases bibliography is the end result of any literature search. For example, Indian National Bibliography, Indian Books in Print, etc.
i) Bibliography of Bibliographies: A bibliography of bibliographies lists the bibliographies which direct the reader to useful bibliographies through subject, place, institution, etc. The bibliographies refereed to may be in the form of a separately published book or part of the book or part of the periodical article or some other type of document. Bibliography of bibliographies is highly selective in nature. For example, Bibliographic Index.
e) Indexing and Abstracting Periodicals: An index is a systematic guide to i) item contained in or ii) concept derived from a collection. These items and derived concepts are represented by entries arranged in a known or stated searchable order. According to Allen Kant, “an abstract is a summary of a publication or articles accompanied by an adequate bibliographical description to enable the publication or article to be traced”.
The indexing and abstracting periodicals present a condensed form of the literature of the subject and provide a scientific or specialist bird’s eye view of the progress and development of the subject so that the inquirer can select the most relevant documents relating to his work in the hand. An indexing and abstracting periodical helps to find out specific information in the literature of a subject.
i) Citation Index: A citation index is an index of citations between publications. It allows the user to easily establish as to which later documents cite which earlier documents. It is an ordered list of cited articles each of which is accompanied by a list of citing articles. The cited articles are identified as references and the citing articles as source. In a simple way it can be said that cited articles are ancestors and the citing articles are descendents and this descending relation of subjects is reflected through the citation index. Citations provide a further reading list besides paying homage to the pionners and giving credit for their work; sometimes it also criticises, corrects and disputes the previous contributions. The first citation indices were legal citators such as Shepard's Citations (1873). In 1960, Eugene Garfield's Institute for Scientific Information (ISI) introduced the first citation index for papers published in academic journals, starting with the Science Citation Index (SCI), and later expanding to produce the Social Sciences Citation Index (SSCI) and the Arts and Humanities Citation Index (AHCI). Examples include ISI citation indexes (available online under the name “Web of Science”), Scopus published by Elsevier publishers (available online only), CiteSeer system publish, Google Scholar (GS), etc.
f) Geographical Sources: Geography is the study of the Earth’s surface and its lands, features, inhabitants, and phenomena, people's responses to topography and climate, and soil and vegetation. Geographical sources of information can be of the following types:
i) Gazetteer: A gazetteer is a geographical dictionary, an important reference for information about places and place-names, used in conjunction with an atlas. It typically contains information concerning the geographical makeup of a country, region or continent, the social statistics and physical features, such as mountains, waterways, or roads. It also includes information about the location of places, dimensions of physical features, population, GDP, literacy rate, etc. World gazetteers usually consist of an alphabetical listing of countries, with pertinent statistics for each one, with some gazetteers listing information on individual cities, towns, villages and other settlements of varying sizes. Examples include The World Gazetteer, Worldwide Index, etc.
ii) Guides: According to ALA Glossary of Library Terms, a guide book has been defined as handbook for travellers that gives information about a city, region or country or a similar handbook about a building, museum, etc.
A guide to the literature assists a user to use literature of a specific subject. It helps to evaluate and introduce literature. It lays emphasis on the literature of a subject rather than its content and covers secondary and tertiary sources. It presents a detailed account of the bibliographical apparatus and tools, basic literature, agencies, etc. through which it is possible to follow the development, status and progress of a subject. It gives the broadest bibliographical view of the subject. A guide to the professional organization gives the address and a brief description of the organizations engaged in a particular field at the national or international level. Guides generally include guides to the literature of a subject, guides to the libraries, guides to organization etc.
iii) Map: A map is defined as “a representation of a part or the whole of the surface of the earth or a celestial body delineated on a plain surface, earth points in the drawing intended to correspond to a geographical or a celestial position”. It represents the outer boundaries of a part of the earth or the earth as a whole on a plain surface. In simple, it is a simplified depiction of a space which highlights relations between components (objects, regions) of that space. Most usually a map is a two-dimensional, geometrically accurate representation, normally to scale, of all or a portion of the three-dimensional earth's surface or of the heavens, or another celestial body. More generally, maps can be devised to represent any local property of the world or part of it. Maps are usually stored in specially designed cases which allow them to lie flat.
iv) Atlas: An atlas is a collection of maps, traditionally bound into book form, but also found in multimedia formats. It gives geographic features, political boundaries and some time geopolitical, social, religious and economic statistics. ALA Glossary defines atlas as “a volume of map, plates, engraving, tables, etc with or without descriptive letterpress”. It may be an independent publication or it may have been issued to accompany one or more volume of text. Some cartographically or commercially important atlases include Times Atlas of the World (United Kingdom, 1920-present); Atlas Mira (Russia, 1937-present); National Geographic Atlas of the World (United States, 1963-present); Historical Atlas of China (China). Some other atlases are thematic. Example: The Times Atlas of World Exploration.
v) Globe: A globe is a three-dimensional scale model of Earth (terrestrial globe) or other spheroid celestial body such as a planet, star, or moon. It may also refer to a spherical representation of the celestial sphere, showing the apparent positions of the stars and constellations in the sky (celestial globe).
g) Biographical Sources: A biography is a description or account of the series of events making up of someone's life, which is usually published in the form of a book or an essay, or in some other form, such as a film. An autobiography is a biography of a person's life written or told by that same person. The biographical information also can be obtained from almanacs, biographical dictionary, directories, encyclopedias, etc. Examples include International Who’s Who, Dictionary of National Biography, etc.
h) Current Sources: Current sources of information are brought out on annual basis that depicts some important happening in the previous year. It may take the form of the following:
i) Year Book: A year book is an annual compendium of current information which may be sometimes restricted by subject or country or region. It is mostly used for answering questions involving the recent trends and current developments. J. K. Cates defines a year book as “a publication which is issued annually for the purpose of current information in narrative, statistical or descriptive form”. According to ALA Glossary, a yearbook is “an annual volume of current information in descriptive and or statistical form, sometimes limited to a special field”.
ii) Almanac: The word almanac (also spelled almanack) is an annual publication containing tabular information in a particular field (mostly covering information about rising and setting of moons, periods of low and high tides, climate or weather related information) often arranged according to the calendar. According to the ALA Glossary, an almanac is a) an annual publication containing a calendar frequently accompanied by astronomical data and other information or b) An annual year book of statistics and other information sometimes in a particular field. It records most of the astronomical data and various statistics, such as the times of the rising and setting of the sun and moon, eclipses, hours of full tide, stated religious festivals, terms of courts, etc. Contents also include discussions of topical developments and a summary of recent historical events. Major topics covered by almanacs (reflected by their tables of contents) include: geography, government, demographics, agriculture, economics and business, health and medicine, religion, mass media, transportation, science and technology, sport, and awards/prizes. Sometimes almanac is grouped with yearbooks as this is also an annual publication giving current events, developments, statistics, etc. Example: World Almanac and Books of Facts, Whitaker's Almanack, Information Please Almanac, The Old Farmer's Almanac etc.
i) Directory: A directory is a list of names and addresses of persons, organizations, manufacturers or periodicals. It may list information in a way which best serves the requirements of its user so as to enable them to get the required information readily. S. R. Ranganathan defines a directory as “a book containing the names, address, occupation, etc of the inhabitants of a town or a district, a list of the user of a telephone system or of the members of a particular profession or trade or a descriptive list of institution, enterprises or trade”. ALA Glossary of library terms defines a directory as “a list of persons or organizations, systematically arranged usually in alphabetical or classified order giving address, affiliation etc. for individual and address, officers, functions and such data for organization”. In a wider sense, even a list of periodicals or newspapers or places may also be termed a directory. Example: Times of India Directory and Yearbook including Who’s Who, Bowker Annual of Library and Book Trade Information, World of Learning, Universities Handbook, etc.
j) List of Research in Progress: A list or directory of research in progress covers the research activities of a single institution, a laboratory or a group of institutions i.e. universities. The information content usually is a short description of projects, names of investigators, period of investigation, and names of funding agencies and, in some cases, reference to sources where preliminary results have already been published or likely sources of publication of results.
List of research in progress helps an individual information seeker to get in touch with the investigation, to get additional information about the work or can anticipate as to when and where to get the full report or results of an investigation and thus to avoid duplication in research. Example: Current research project in CSIR Laboratories, 1972 and 1976 compiled by INSDOC, R and D Projects in Documentation and Librarianship of FID.
k) Notification of Forth Coming Conferences: The knowledge of forth-coming meetings, conferences, symposia, seminar, etc. on a specific field should be notified to the members belonging to that specific domain. Keeping this purpose in view some organizations publish small booklets giving essential general information about forth-coming seminar, conference and workshop in a specific field. Example: Forthcoming International Scientific and Technical Conference, Quarterly published by ASLIB.
l) Handbook: The term “hand book” literally comes from the German word “handbuch” i.e. a book which can be held in the hand comfortably. It is a compilation of miscellaneous information in a compact and handy form. It is a small manual, reference work or other collection of instructions, intended to provide ready reference regarding procedures, principles, etc. table, graph, diagram and illustration are also provided. Louis Shores has defined handbook as “a reference book of miscellaneous facts and figures on one or many subjects assembled for ready use in response to popular interest or to a specific need for concise handy information”.
m) Manual: The word “manual” is derived from the Latin term “manualis” which means a guide book or instruction book to pursue an occupation, art or study. The term “manual” in common parlences refers to instruction to do something with the aid of very explicit step by step directions. It gives instruction by means of specific and clear direction. Louis Shores opined that “manuals are sources that contain instruction for doing”. ALA Glossary defines a manual as a) a compact book, a handbook b) a book of rules for guidance or instructions in how to perform a task, process etc. or make some physical subjects. Example: Fay, G.S. (1972). Rockhound’s Manual. New York: Harper and Row.
n) Statistical Sources: The statistical information is distributed in other reference sources. The dictionaries may contain population statistics. The encyclopedia may provide socio-economic data about large geographical areas, which may be updated by their yearbook; the statistical yearbook may provide some other kinds of statistics over a longer period of time, and so on. Example includes Demographic Yearbook, Statesman’s Yearbook, etc.
o) Mathematical Table: In early days before calculators were cheap and plentiful, people were using mathematical table i.e lists of numbers showing the results of calculation with varying arguments to simplify and drastically speed up computation. The most common are multiplication tables, which most people know from their early mathematics classes. Nowadays, peple use logarithm tables and so on.
Some of the reference sources overlap. For instance a supplement to an encyclopedia can be considered as a part of encyclopedia or separately. Similarly, the sources of statistics can be considered under yearbook or as a separate category.
Many of the above sources are now available in audio- visual format or as an online publication but still they can be included under their respective categories. Besides, the traditional reference sources, Search engine, Meta search engines can also be considered as reference sources of modern times.