An APA website citation is particularly used for sources that you have accessed and taken online, such as websites, web pages, and even online databases, online encyclopedias, and other internet archives. For these works that you have retrieved online, two additional pieces of information should be included in your citation entry. One is the internet address, commonly called as a URL (Uniform Resource Locator), which identifies the location of the file on the internet, consisting of the protocol, the computer on which the file is located, and the file’s location on the computer.
A stable and working internet address or URL of the work from which you took your source should be included in your APA website citation entry, and, when clicked or visited, should direct the reader to the web page where the actual work is located. If the particular work has a digital object identifier, or DOI, the APA style recommends you to use this instead. If there is no DOI or similar handle, the URL should suffice. If the specific URL is liable to change, as in some cases, especially with online versions of newspapers and some subscription-based databases, you need to use the main internet address of home page of the site you retrieved the work from.
Additionally, the APA website citation should also contain the date in which you accessed and retrieved the work or information online. Sometimes, if the particular work that you intend to cite is a finalized version and published online on a specific date, as in the case of most journal, magazine, and newspaper articles, you need to include it within the main body of the citation entry. On the other hand, if the work is not dated and/or is subject to change, as in the case of an online encyclopedia article, you only need to include the date when you retrieved the information.
Below are some citation examples:
Last, M. Love Poems for Her. In Love Poems for Her. Retrieved July 8, 2012, from http://lovepoemsforher.net
For an online source that has no author:
Albert Camus. In Wikipedia: The Free Encyclopedia. Retrieved July 8, 2012, from http://en.wikipedia.org/wiki/Albert_Camus
New Child Vaccine Gets Funding Boost. In Medical Headlines: Health News. Retrieved July 8, 2012, from http://news.ninemsn.com.au/health/story_13178.asp
For an APA website citation of multiple authors:
Van Vugt, M., Hogan, R., & Kaiser, R. B. (2008). Leadership, Followership, and Evolution: Some Lessons from the Past. In American Psychologist. Retrieved July 8, 2012, from doi:10.1037/0003-066X.63.3.182