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Extract from Wikipedia
Serial comma
From Wikipedia, the free encyclopedia
In English language punctuation, a serial comma, or series comma (also called an Oxford comma or a Harvard comma), is a comma placed immediately before the coordinating conjunction (usually and or or) in a series of three or more terms. For example, a list of three countries might be punctuated either as "France, Italy and Spain" (without the serial comma) or "France, Italy, and Spain" (with the serial comma).
Opinions among writers and editors differ on whether to use the serial comma, and usage also differs somewhat between regional varieties of English. British English allows constructions with or without this comma, while in American English it is common and even often considered mandatory.
A majority of American style guides mandate use of the serial comma, including APA style, The Chicago Manual of Style, Garner's Modern American Usage, The MLA Style Manual, Strunk, White's Elements of Style and the U.S. Government Printing Office Style Manual. In contrast, the Associated Press Stylebook advises against it.
In Canada, the stylebook published by The Canadian Press advises against it. Most British style guides do not mandate its use. The Economist Style Guide notes that most British writers only use it where necessary to avoid ambiguity. However, a few British style guides mandate it, most notably The Oxford Style Manual.
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