This same process works for finding periodicals in the library catalog and on the shelf. Let's say you had this citation for an article:

Smith, Anne Kates. "Scanning for scams, or invading privacy?" US News and World Report. April 10 2000: 45.

By searching the library catalog for the periodical title US News and World Report, you could see if your library owns that magazine. Once you have the call number or location, you can find the periodical, using the page numbers, locate the article within it.

In large libraries many items on the same subject -- books, periodicals, and even movies and CDs -- will have similar call numbers in the library catalog and on the shelf. It is important to write down the entire call number in order to locate the item.