In the previous lesson, you learned how to use library catalogs to look for books on your subject. Books are good sources for in-depth exploration of your topic. However, because the publication of a book may take several years, by the time a book is actually released its ideas may already be obsolete. Many topics, particularly in the sciences, require more current research in periodicals.

Periodicals is a general term used to refer to newspapers, magazines and journals (publications that are published "periodically".) In some libraries, especially larger research libraries, the term "serials" is used more commonly than "periodicals."

Periodical articles are often the best source for finding the most current and concise information on a topic. A variety of different periodical articles can provide varied perspectives on a topic and can often provide references to additional information.

Newspapers provide first-hand accounts of current events in their news reports; these reports are primary sources. In their editorials and opinion pieces, newspapers present diverse points-of-view on controversial issues.

The distinction between magazines and journals is not always very precise, but it is important to understand the general differences between these types of publications. Popular magazines (such as Time, Newsweek or Sports Illustrated) include those found on most newsstands, usually with flashy covers intended to entice a reader and commonly printed on glossy paper with many illustrations and photographs. Magazines are usually written by journalists for a fairly general audience so they are usually easier to read than journals, but the information they provide tends to be less detailed or authoritative. Footnotes and bibliographies are rarely included in popular magazine articles. Browsing through popular magazines can sometimes be a useful method of finding an interesting topic for a research project. Articles in popular magazines usually provide some general overview information on current events, issues and trends.

 Scholarly journals tend to be the most common sources of bibliographic research for serious researchers. These journals are usually oriented to students and professionals in a particular discipline and may be more difficult to understand for those who do not have some familiarity with the general field being discussed. Subject coverage tends to be more specialized and articles usually reflect the most recent research and important issues being discussed in a particular academic area. Scholarly journal articles usually review previous literature and report original research and almost always include extensive footnotes and bibliographies. Many scholarly journals are "refereed"--articles submitted for publication are reviewed by authorities in the field to determine whether they are acceptable to be published. Scholarly journal articles are often preceded by an abstract--a brief summary of the article.

An example of a scholarly journal is Psychological Science: A Journal of the American Psychological Society. This journal presents authoritative articles of interest to academic and professional psychologists: it covers all of scientific psychology's subdisciplines--including cognitive science, neuroscience, linguistics, and social sciences; the journal is intended as a forum for psychologists to learn and disseminate research, theory and application in the field of psychology. The academic affiliation of each author is indicated at the head of every article; also, every article includes and abstract. As with other scientific journals, every issue of Psychological Science features summaries of new research developments, and reviews of new publications.

Between popular magazines and scholarly journals are subject magazines (such as Scientific American or Smithsonian), professional journals (such as Anthropology Today or American Psychologist) and trade journals (such as Automotive News or PC Week). These types of publications sometimes look similar to popular magazines but they typically report on developments in a particular subject area, profession, trade or industry and are oriented to those who are either in the field or who have a particular interest in the subject matter. They differ from scholarly journals in that their articles do not usually include original research and, although they are often written by subject experts, the writing tends to be less complex and technical.

It is important to understand the use of each type of periodical in the research process.

Each type of literature has a function and value in research. Popular articles often make a good point of entry for research. They can provide a basic introduction to a topic, an overview that may suggest possible approaches to the subject, divergent points of view, and perhaps some color. The college-level researcher will go on to collect scholarly articles that offer more focused, in-depth, original, research-based information. Subject or professional magazines may serve both sets of functions and are particularly useful for research in scientific and technical areas in which the scholarly materials may be too specialized for undergraduates. They offer the authority of experts without the complexity of original research accounts.
 

To find articles on a specific topic in different periodicals, essentially two types of periodical indexes are used: general periodical indexes and specialized indexes. These periodical indexes list articles in a particular set of periodicals. 

General Indexes

"General indexes" provide basic citations under subject headings and authors for articles in a wide range of popular magazines and larger subject magazines and professional journals. Readers' Guide to Periodical Literature (published by H.W. Wilson), available in print, CD-ROM and online versions, is the oldest and most well-known general index, but there are a number of increasingly popular competitors in the CD-ROM and online formats, including InfoTrac Academic ASAP and InfoTrac General Reference Center (formerly Magazine Index) (both from Information Access Co.)

Specialized indexes

 Subject periodical indexes are used in the same way as general periodical indexes, but the publications indexed tend to be more scholarly and professional journals and subject magazines all focused on a particular subject area.

Some subject periodical indexes are very comprehensive, trying to index almost every journal published in a particular field of study, while others are more selective, including a limited number of the more important, less specialized magazines and journals in a subject area. H.W. Wilson Company, the company that publishes Readers' Guide, produces a number of the more selective types of periodical indexes, including Art Abstracts, Business Periodicals Abstracts, General Science Abstracts and Social Sciences Abstracts. Other specialized indexes include InfoTrac Business and Company ASAP and InfoTrac Health Reference Center. All of these commonly-used subject indexes are especially oriented toward undergraduate students.

The list of periodical indexes covering specific subject areas is extensive and includes virtually every field of study. Some of the more comprehensive, most well-known subject indexes include: Psychological Abstracts, Sociological Abstracts, BIOSIS (biology), Medline (medicine), ERIC: Educational Resources Information Clearinghouse (education), PAIS: Public Affairs Information Service (political science), ABI/Inform (business information), America: History and Life (American history), Historical Abstracts (world history) and INSPEC (physics, electronics and computing.)

Both general and specialized periodical indexes may contain abstracts and full-text. Abstracts are brief summaries of indexed articles. Each abstract is generally from a couple of sentences to a few paragraphs in length. Full-text means the complete text of the articles are included, but not any pictures or other graphics. Indexes which contain abstracts and full-text include InfoTrac Academic ASAP, InfoTrac General Reference Center and Readers' Guide Abstracts.

Articles may be accessed in a variety of ways by different indexes, but subject headings and authors are most common. Under each subject or author (usually alphabetically arranged) you will find citations for the periodical articles. A citation contains the information you need to find the article mentioned.

Each citation contains the following information:

Here is an example of a citation from Infotrac Academic ASAP:

Figuring out the best subject headings to use in periodical indexes is often more difficult than in catalogs because each index uses a different list of subject headings (although some use the Library of Congress Subject Headings-see Unit 1) and those lists are not always published.

Cross references

Most periodical indexes use cross-references to direct users to other subject headings.

A "See" reference refers you to the correct term or wording to use in that index to locate information about that subject. For example:
If you wanted to find articles about immigration, a "See" reference would refer you to the subject: "Emigration and Immigration".

A "See also" reference suggests additional or related subject headings. For example:
In the Academic ASAP database, by selecting the "See also 9 related subjects" reference under the subject "Emigration and Immigration", you would then find links to articles on related topics, such as "Naturalization", "Population Transfers" and "Repatriation."

Sub-headings or Subdivisions

Within each subject section, there may be sub-headings or subdivisions. Sub-headings or subdivisions divide the main subject heading into more specific aspects of the subject. For example:
In Academic ASAP, if you were interested in locating articles about the economic effects of immigration, you could look up the main heading "Emigration and Immigration", and then select "See also 56 subdivisions". You could then find the specific subdivision "economic aspects" on the list of subdivisions for that subject heading.

If the full-text of the article is not accessible in the periodicals database, you will need to locate the periodical in the library.

To find out which periodicals are carried by a particular library, you can use a "periodicals list" or "serials list". Some libraries include their periodicals in their main catalog, but many maintain a separate alphabetical list of periodical titles. These lists often indicate where each periodical is located in the library. In some libraries older copies of periodicals (called "back issues) are available on microfilm or microfiche or are bound (like books) and are shelved in the regular stacks. In other libraries, back issues are kept in a separate periodicals section.

At Skyline Library, a list of the library's periodicals is available at the reference desk. This list identifies what dates are available for each periodical title and where each title is located (whether in print, on microfilm or bound.) All periodicals available at all of the Peninsula Library System libraries are listed in the PLANET online catalog. To look up a periodical title in the PLANET catalog, select the "TITLE" search mode from the main PLANET search menu.

To find out which periodicals are carried by other libraries in an area, you can often refer to a "union list of periodicals", which includes all periodicals carried by a group of different libraries. In addition to listing periodicals on the PLANET catalog, the Peninsula Library System publishes a Union List of Periodicals that lists all of the periodicals available at all of the PLS libraries. At Skyline Library, the PLS Union List of Periodicals is available at the reference desk.