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Citation Styles

The moment you are asked to cite, take a look at your assignment to see if a specific citation style is indicated. This information must be known before you can properly cite your work. As with any citation system, using it correctly protects you from accusations of plagiarism. Three common citation styles are below. Click on the tabs on the right to learn about four common citation styles: MLA, APA, Chicago Manual of Style, and AMA.

MLA (Modern Language Association) style is widely used in the humanities, especially in writing on language and literature. It provides writers with a system for referencing their sources through parenthetical citation in their essays and Works Cited pages. If you are asked to use MLA format, be sure to consult the MLA Handbook for Writers of Research Papers (7th edition), which can be found in the reference section of the library

APA (American Psychological Association) style is most commonly used to cite sources within the social sciences. This resource, revised according to the 6th edition of the APA manual, offers examples for the general format of APA research papers, in-text citations, endnotes/footnotes, and the reference page

The Chicago Manual of Style (CMS) covers a variety of topics from manuscript preparation and publication to grammar, usage, and documentation.

There are two main styles:

  • The Notes-Bibliography System (NB), which is used by those in literature, history, and the arts.
    • The Chicago NB system is most often used in history and is often used in the humanities and provides writers with a system for referencing their sources through footnote or endnote citation in their writing and through bibliography pages.
    • As with any citation stystem using it correctly protects the writer from accusations of plagiarism. As mentioned earlier in this guide proper citation builds credibility to the paper by demonstrating accountability to source material.
    • Sample Paper in Notes-Bibliography (from Purdue OWL)
  • The Author-Date System, which is preferred in the sciences.
    • In the Author-Date System each citation consists of two parts: the text citations, which provides brief identifying information within the text, and the reference list (list of sources used) which provides full bibliographic information.
    • Descriptions for Style Guides (APA). Russell, T., Angeli, E., Wagner, J., Lawrick, E., Moore, K., Anderson, M., Soderland, L., & Brizee, A. (2010, August 1, 2010). General format. Retrieved from
    • Sample Paper in Author-Date (from Purdue OWL)
  • If you are asked to use the CMS, be sure to consult the Chicago Manual of Style, 16th edition, which can be found in the reference section of the library, call number REF Z253.U69 2010

The reference style followed by JAMA and its related journals was developed from recommendations contained in the ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals  (formerly known as the Vancouver style) and the National Library of Medicine's recommendations found in Citing Medicine:The NLM Style Guide for Authors, Editors, and Publishers.


Online Writing Lab (OWL) at Purdue

The OWL at Purdue has a series of guides for formatting and citing papers using style guides.

Search "sample papers" in OWL to find written and correctly cited papers in MLA, APA, and CMS for your reference. OWL also defines, formats, and explains the significance of Annotated Bibliographies.