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Citation Guide

What is a Citation?

citation is a reference to a published or unpublished source. A citation is an abbreviated alphanumeric expression embedded in the body of an intellectual work that denotes an entry in the bibliographic references section of the work for the purpose of acknowledging the relevance of the works of others to the topic of discussion at the spot where the citation appears. Generally the combination of both the in-body citation and the bibliographic entry constitutes what is commonly thought of as a citation (whereas bibliographic entries by themselves are not). 

Citations have several important purposes: to uphold intellectual honesty or avoiding plagiarism, to attribute prior or unoriginal work and ideas to the correct sources, to allow the reader to determine independently whether the referenced material supports the author's argument in the claimed way, and to help the reader gauge the strength and validity of the material the author has used. 

The forms of citations generally subscribe to one of the generally accepted citations systems, such as American Psychological Association (APA), Modern Language Association (MLA), Chicago American Medical Association (AMA), Oxford, Harvard, American Sociological Associations (ASA),  and other citations systems, because their syntactic conventions are widely known and easily interpreted by readers. Each of these citation systems has its advantages and disadvantages. Editors often specify the citation system to use. Electronic sources also come with their own specific citation rules in each of these styles. It is important to learn proper citation styles to avoid plagiarism in your research papers. 

With APA or any of the styles listed in this paper, you need to use a citation if you quote text from another source, paraphrase an author or authors' ideas, or refer to her work, such as a study, original thinking, or even an elegant turn of phrase. When you cite a source, you cannot simply repeat most of the words from the work to which you are referring. You have to put the ideas into your own words, or you need to quote the text directly.

APA Citations

American Psychological Association (APA) style is often used in social sciences and other disciplines. APA  is most commonly used to cite sources within the social sciences. This resource, revised according to the 6th edition, second printing of the APA manual, offers examples for the general format of APA research papers, in-text citations, endnotes/footnotes, and the reference page. For more information, please consult the Publication Manual of the American Psychological Association, (6th ed).

MLA Citations

MLA style is most commonly used to cite sources within the language arts, cultural studies, and other humanities. This resource, revised according to the 8th edition of the MLA manual, offers examples for the general format of MLA research papers, in-text citations, and the Works Cited page. For more information, please consult the official MLA Handbook

Chicago Citations

The Chicago Manual of Style (CMOSis the oldest of the three major writing and citation styles in the United States, having begun with the 1906 publication of the first Chicago style guide.This style covers a variety of topics from manuscript preparation and publication to grammar, usage, and documentation and has been lovingly called the “editor's bible.” The material in this resource focuses primarily on one of the two CMOS documentation styles: the Notes-Bibliography System (NB), which is used by those in literature, history, and the arts. The other documentation style, the Author-Date System, is nearly identical in content but slightly different in form and is preferred in the social sciences.

In addition to consulting The Chicago Manual of Style (16th ed) for more information, students may also find it useful to consult Kate L. Turabian's Manual for Writers of Research Papers, Theses, and Dissertations (8th ed.). This manual, which presents what is commonly known as the "Turabian" citation style, follows the two CMOS patterns of documentation but offers slight modifications suited to student texts.

AMA Citations

This resource discusses references page formatting for the American Medical Association (AMA) style sheet. AMA was developed by the American Medical Association for the purpose of writing medical research. For more information, please consult with Purdue Owl AMA style page.


Nordquist, R. (2018). What Is a Citation? Definition, Styles, and Examples. Retrieved   from

PURDUE Online Writing Lab (OWL). Retrieved from

What you don't have to cite

You do not have to cite:

  • Your own experiences, artwork, data or findings compiled from your own research work.
  • Common knowledge - facts known to most people and found in most reference resources, widely known historical or geographic facts. Common knowledge can also include information your teacher would expect all students to know, in other words it can include some specific information widely known in a field of study such as nursing, business or the social sciences. 
  • Remember, when in doubt, cite it.

Citation Samples