Summarize this article:

This only applies if the textbook has a fixed URL and does not apply to e-books that are borrowed from the library or purchase. The URL is not always necessary to include and is formally a matter of instructor preference.Doe, John and Bob Smith. The Interesting Textbook. Ed. Richard Hoffman, 3rd ed., Big Time Publishing House, 2010. EBSCOhost. <http://www.sampleURL.com>.

Summary:
Specify the URL, if applicable or desired.