Type a pair of parentheses at the end of the sentence that references the Wikipedia source.
Write the title of the Wikipedia article inside the pair of parentheses, followed by a comma. If the title contains multiple words, only write the first one or two words. Enclose the article title and the comma in quotation marks. For example, to cite the article "User-Generated Content," you would write ("User," ). Normally, you would cite the author here, but when a reference lacks an author -- common among wikis or other encyclopedia-type sources -- APA style instructs you to use the title of the entry instead.
Type a space, then write the abbreviation "n.d." just before the ending parenthesis; for example: ("User," n.d.). Usually, you would write the year of publication. "N.d." stands for the phrase "no date," meaning that the Wikipedia article lacks a specific publication date. This information helps readers find the reference entry in the reference list, and it also signifies the source's possible lack of credibility and stability.
Type a period, or some other mark of punctuation that ends a sentence, immediately after the final parenthesis; for example: ("User," n.d.).
Write the full title of the Wikipedia article, and capitalize all of the major words (usually excluding prepositions with three letters or fewer). For example, to cite the article "User-Generated Content," write: User-Generated Content. Unlike in the text of the paper, don't enclose the title in quotation marks. At the end of the title, type a period and then a space.
Add a set of parentheses; inside them, type the abbreviation "n.d." in lowercase letters. Immediately after the parentheses, type another period and then type a space. The citation will now look like this: User-Generated Content. (n.d.).
Write the word "In" -- in normal text -- and then write the word "Wikipedia" in italics. Return to normal text, type a period and then type a space. The citation should now follow this format: User-Generated Content. (n.d.). In Wikipedia.
Write a retrieval statement, which specifies when you accessed and read the Wikipedia article. APA style doesn't require a retrieval statement for permanent online sources, but Wikipedia articles can change at any moment, and they often undergo updating or editing; hence, your readers need to know when your information was current. First, write the word "Retrieved" and type a space. Next, spell out the full name of the month, followed by a space and then the numeral of the specific day. Add a comma and another space, then type the year. Add a comma and a space, write the word "from" and then add one last space. The end result should follow this pattern: Retrieved January 1, 2011, from.
Add the exact URL of the Wikipedia article. To ensure complete accuracy, copy the URL from your Web browser and paste it directly into the document containing your paper.
Don't add any punctuation to the end of the citation; after pasting the URL, you have completed the citation. For example: Retrieved January 1, 2011, from http://www.wikipediaexample.com