The following is reprinted from The Bluebook: A Uniform System of Citation (19th ed. 2010).
18.2.2 Direct Citations to Internet Sources
An Internet source may be cited directly when it does not exist in a traditional printed format or when a traditional printed source, such as a letter or unpublished dissertation, exists but cannot be found or is so obscure that it is practically unavailable. All efforts should be made to cite to the most stable electronic location available. The Internet citation should include information designed to facilitate the clearest path of access to the cited reference, including the title, pagination, and publication date as they appear on the webpage. The Internet URL should be separated by a comma and appended to the end of the citation (that is, not preceded by “available at” or “at”).
Below is an example of a direct citation to an internet source:
Eric Posner, More on Section 7 of the Torture Convention, Volokh Conspiracy (Jan. 29, 2009, 10:04 AM), http://www.volokh.com/posts/1233241458.shtml.
Use Colum. Sci. & Tech. L. Rev. as the abbreviation for the Columbia Science and Technology Law Review.