The APA style guide format has two types of citation formatting: the citation in the paper and the citation at the end of the paper. The citation in the paper is inserted at the end of the thought being referenced. For example, after a quote, the author or authors and the date of the publication should appear in parentheses. If the author or the date of the publication is referenced in the sentence, the parentheses aren't needed. For books with more than three authors, reference all authors in the first citation, and for all subsequent citations use the first author and add "et al." thereafter. To reference a whole book, start with the author, followed by the date in parentheses, then the title italicized and finally the publishing house. Each section is separated by a period. In a journal, APA format uses all of the same information that a book citation requires. Start with the author of the journal, the date in parentheses, the full title of the article and then the name of the journal italicized. The title of the journal and the volume number should both be italicized and separated by a comma. A period separates every other section, including the italicized journal number from the page numbers.
Website citations should also be indented after the first line. A period separates each section of the citation To cite a website: Start with the name of the author then the date. The title of the website page follows the date; the title should be in italics. Last is the URL, which should be introduced with "Retrieved from http://(enter URL here).com".
APA is not the only style guide for writing science and social science theses and papers. There is also the Chicago, ASAMLA, ACS and APSA. Each style has a different set of rules, so make sure to ask an editor or professor which style they would prefer.
APA stands for the American Psychological Association. This association has put together a book with hundreds of guidelines on how to format sources, proper punctuation points and grammar etiquette. Each year the book is updated with new style points and any changes in grammar or punctuation throughout the year. APA is the most commonly used style guide for research and thesis papers.