A newsletter is a circulated publication that distributes information, often informal, among a certain group of people. Because of the informal nature of a newsletter, some people overlook the fact that they must be cited just like any other source. The correct format for citing a newsletter will depend on whether you are using the American Psychological Association, APA, or the Modern Language Association, MLA, style guidelines. APA style does not specify specific guidelines for newsletters. It is best to use the general form for citing an article within a periodical.