Types of sources. Look at the Directory to Chicago Style on p. 500. You will need to be careful to tell your readers whether you read a print version or a digital version of a source that consists mainly of written words. Digital magazine and newspaper articles may include updates or corrections that the print version lacks; digital books may not number pages or screens the same way that a print book does. If you are citing a source that has media elements—such as a film, a song, or artwork—consult the “other sources” section of the directory. And if you can’t find a model exactly like the source you’ve selected, see the Checklist on p. 506.

articles from web and database sources.You need a subscription to look through most databases, so individual researchers almost always gain access to articles in databases through the computer system of a school or public library that pays to subscribe. The easiest way to tell that a source comes from a database, then, is if its information is not generally available free to anyone with an Internet connection. Many databases are digital collections of articles that originally appeared in edited print periodicals, ensuring that an authority has vouched for the accuracy of the information. Such sources may have more credibility than free material available on the Web.