When you use the information and perspectives you found in other sources, citations give credit to the ideas of others and make you a more credible author. They can also help your readers find the same sources again. Citation styles are guidelines and conventions that different disciplines follow to present writing and sources in a consistent way. APA style, from the American Psychological Association, is a common citation style used in the sciences and social sciences. There are two main components of a citation. First, when you reference another source, include an in-text citation in the body of your paper. In APA style, this citation includes the author's last name or organization, comma, and the year in parentheses. If there are more than three authors, include the first author's last name, then use the abbreviation at all, which means and others. Then, include a complete citation in the reference list at the end of your paper. Your in-text and reference list citations should match. A reference list citation typically includes the author, the date, the title of the work, and the source, or information about where you can get it, including any URLs or other links. Each part is separated with a period. In the reference list, use a hanging indent and organize your references alphabetically by author's last name. This helps your readers skim through the list to find the reference for an in-text citation. Reference list citations vary based on the type of source you're citing and the information available. Use the official style manual or an online citation guide to check which details about the source you should include. Let's take a look at one example. In college, you'll probably be citing a lot of academic journal articles. First, include the last names and initials of the authors. Use the ampersand sign for AND before the last author. Then include the year the article is published in parentheses. Next, include the title of the article in sentence case. This means only the first word of the title and subtitle and any proper nouns are capitalized. After that, include the academic journal where the article was published in italics. Academic journals publish collections of articles throughout the year. A journal might have a volume for each year and publish a new issue every few months. Separate the journal and the volume with a comma and italicize the volume number two. If there is an issue number, include that in parentheses and add the page range. Finally, include the DOI or digital object identifier if it's available. This is a direct link to the article on the publisher's site. Formatting citations and your paper can require some attention to detail. If you're not sure how to cite a source using APA style, ask a librarian.