This document provides an overview of the APA and MLA citation styles. It defines APA as the style of the American Psychological Association and MLA as the style of the Modern Language Association. Both are used to cite sources in research papers and require in-text citations and bibliographies that are formatted differently. The key differences between APA and MLA are that APA is more commonly used in scientific and social science fields, while MLA is used more in language and literature fields. Both require double spaced papers with 1 inch margins but have different rules for page headers and bibliographies.