APA style citation, along with other styles including MLA, Harvard and Chicago, is widely recognized in academia. While it is sometimes up to the student or researcher to choose the citation style as he/she sees fit, professors or even the entire academic institution often selects a style that they expect all of their writers to follow. Always include an in-text citation whenever your paper is summarizing, paraphrasing or directly quoting an outside source. Furthermore, the sources that you cite within the paper must also be included in the bibliography page. Note that the guidelines for APA citation often differ from other styles, so it is important to ensure that your paper is consistent in following the proper rules.