Periodical is simply the generic name for a publication that comes out on a regular or "periodic" rate, including magazines, journals and trade publications. For example, newspapers are periodicals most often published daily and magazines are often published weekly.

Abstracts — brief summaries that are included in most databases.

Citation — used to document sources and usually includes author, article title, periodical title, volume, issue, date, and page number(s), the necessary information to find the article. For electronic resources (databases and web sites) you may need additional information when writing a citation, such as APA's "doi" (opens new windowdigital object identifier).

Digital Object Identifiers, or DOIs — persistent links used in scientific and scholarly publishing to provide a permanent electronic address to avoid the problems of broken, outdated or changed links. The DOI System provides a means for managing information in changing digital environments. opens new windowWhat is a digital object identifier, or DOI? (APA Style) opens new windowDOIs and URLs (APA Style)

Full text — refers to the complete article; most often in electronic format.

Index— points to where the information can be found; similar to the index of a book. Some databases are indexes and, as such, include citations of articles but no full text though they may include abstracts. Although there are print indexes, most periodical indexes are online databases.

Peer reviewed— means experts in the field evaluated the validity of an article before publication. Refereed refers to journals or articles that are peer reviewed.

Scholarly— refers to articles based on research. Scholarly articles included references. the opens new windowCQ Researcher is scholarly, as it is based on and includes footnotes and a reference list; however, it is not peer-reviewed.

• Contains articles of interest to the public.
• No peer-reviewed articles.
• Articles do not have bibliographies.
• Frequently published weekly.

Examples:
opens new windowNewsweek Global
opens new windowControl Engineering
opens new windowConsumer Reports

• Directed toward a discipline, subject, or professional group.
• May include scholarly articles, popular topics, conference information, trends etc.

Example:
opens new window Library Journal
opens new windowComputers in Entertaining

• Contain scholarly articles written by experts concerning research in professional and academic fields.
• Articles include a reference list, bibliography, end notes, or similar documentation.

Examples:
opens new windowStudies in Latin American Popular Culture
opens new windowAmerican Journal of Sociology.