They may require that you use only scholarly articles or limit the number of popular articles that you are able to use. Click on the underlined terms above to get an explanation of these terms and examples of each kind of database. For more information on scholarly vs. popular sources, see Distinctions among Types of Periodicals . Articles in discipline-based databases will usually have less jargon, and those found in general interest databases will normally use common terms. For example, if you want to find articles about the Vietnam War that were written at the time of the war, you will need to search a print index.
Many electronic databases have a print index counterpart that covers the needed time period.