Citation Styles Guide: APA, MLA, IEEE, Turabian, and Chicago

Written by

Mark Robert

15 mins read
 citation styles

Are you writing a paper and not sure which citation style to use? Do you know how to write in-text citations and reference lists?

There are a variety of citation style guides that students may be required to use in their academic papers. Here we provide an overview of five common citation styles: APA, MLA, IEEE, Turabian, and Chicago.

Knowing which style is required for your assignments can help you save time and avoid frustration when formatting your citations.

Let's take a closer look at each of these citation style guides now.

What is a Citation Style?

Citation style helps you credit other people when you use their work for reference in your writing. Citing the referenced work is crucial in academic writing. If you use the work of someone else, you should cite them properly and pay them the credit they deserve.

It is also important to cite sources properly and accurately to avoid plagiarism.

Citation style guides are usually published in handbooks. These handbooks include the rules and explanations. Usually, a citation includes the author’s name, publishing date, paper title, publication information, and DOI (Digital Object Identifier).

How Many Citation Styles Are There?

There are many citation styles available for every academic discipline. The four most common styles are MLA, APA, Chicago, and Turabian.

Other different citation styles are listed below:

  • Institute of Electrical and Electronics Engineers (IEEE)
  • American Political Science Association (APSA)
  • American Anthropological Association (AAA)
  • American Medical Association (AMA)
  • National Library of Medicine (NLM)
  • American Chemical Society (ACS)
  • Vancouver Citation Style
  • Turabian Citation Style
  • Harvard Citation Style

Why Are There Different Citation Styles?

Different academic disciplines have different citation styles. Citation styles often contain similar items—for instance, the paper’s title, author’s name, publication date, and digital object identifier (DOI). However, conventions for each style differ. For example, some styles require uppercase letters while others do not.

A citation convention contains the formatting rules and how to present specific information in a citation.

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Citation Formats - What are the Different Citation Formats?

There are many different citation styles, each with its own rules for formatting, in-text citation, reference list. When using a citation style in your paper, it’s important to review the style rules carefully.

Numeric Citation

This style of citation is used in the scientific community and is known as numerical citations. All citations are numbered in brackets, referring to the full citations listed in the bibliography.

The list is arranged numerically and presented at the end of the paper.

Parenthetical Citation

This citation style is commonly used in humanities discipline citation styles. Each in-text citation is placed in parentheses, referring to a corresponding entry from the reference list. Your last name and page number are cited, for example (Smith 150).

Note Citation

This citation style is used for citing sources in the social sciences discipline. It provides a numbered footnote or endnote with a corresponding entry in the reference list.

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List of Citation Styles - What are the Different Citation Styles?

The citation style you choose for your paper depends largely on the discipline in which you are writing. Disciplines are divided into three categories: science, humanities, and social sciences. All academic disciplines have their particular citation styles.

Professors usually specify a citation style that you should follow when doing your paper.

Citation Styles for Sciences

There are five different citation styles for the science discipline, namely IEEE, ACS, NLM, AMA, and Vancouver. Most science writers use either IEEE or ACS citations.

  • Institute of Electrical and Electronics Engineers (IEEE)
  • IEEE (Institute of Electrical and Electronics Engineers) citation style is common in technical studies. Such as those in electrical engineering, computer science, and information technology.

    For in-text citations, use numeric citation style to cite each source. In the reference list, sources are listed in numerical order. The source entries are indented by a single space.

    The IEEE citation, for example, has rules for citing sources from books, journals, conference papers, and so on. It’s closely related to the citation style used by the Chicago Manual of Style in the Humanities Group.

    IEEE Citation Style Example

    Category Work Cited
    Book D. Sarunyagate, Ed., Lasers. New York: McGraw-Hill, 1996.
    Journal Article A. Vaskuri, H. Baumgartner, P. Kärhä, G. Andor, and E. Ikonen, "Modeling the spectral shape of InGaAlP-based red light-emitting diodes," Journal of Applied Physics, vol. 118, no. 20, pp. 203103-1–203103-7, Jul. 2015. Accessed on: Feb. 9, 2017. [Online]. Available doi: 10.1063/1.4936322
    Conference Paper V. Chandrasekaran, S. Sanghavi, P. A. Parrilo, and A. S. Willsky. (2009). Sparse and low-rank matrix decompositions. Presented at IFAC 2009. [Online]. Available: article/pii/S1474667016388632
    Thesis or Dissertation O. Williams, “Narrow-band analyzer,” Ph.D. dissertation, Dept. Elect. Eng., Harvard Univ., Cambridge, MA, 1993.
  • American Chemical Society (ACS)
  • A. ACS citation style is often used in chemical and biological discipline papers. The American Chemical Society has recommended the following variations for in-text citations:

  • Author name and year of publication: The author’s name and publication date is mentioned in parenthesis on the line of text.
  • A. The primary structure of an enzyme has also been determined (Finnegan et al., 2004).

  • Italic numbers: An italicized number is mentioned in parenthesis inside the punctuation on the line of text.
  • A. The mineralization of TCE by a pure culture of a methane-oxidizing organism has been reported (6).

  • Superscript numbers: A number appears on the punctuation at the end of a line or clause.
  • A. Oscillation in the reaction of benzaldehyde with oxygen was reported previously.3

    In all three variations, the name could be made part of the sentence, i.e., Johanson3, Arif(9). When choosing a style, keep in mind the subject matter or the journal paper you are writing.

    ACS Citation Style Example

    Category Work Cited
    Book Le Couteur, P.; Burreson, J. Napoleon’s Buttons: How 17 Molecules Changed History; Jeremy P. Tarcher/Putnam: New York, 2003; pp 32–47.
    Journal Article Klingler, J. Influence of Pretreatment on Sodium Powder. Chem. Mater. 2005, 17, 2755–2768.
    Thesis or Dissertation Mäckel, H. Capturing the Spectra of Silicon Solar Cells. Ph.D. Thesis, The Australian National University, December 2004.
  • National Library of Medicine (NLM)
  • NLM is the standard style of citation in the medical world, including biology and medicine. NLM uses the numerical in-text citation style to cite sources within text.

    NLM Citation Style Example

    Category Work Cited
    Book Murray PR, Rosenthal KS, Kobayashi GS, Pfaller MA. Medical microbiology. 4th ed. St. Louis: Mosby; 2002.
    Journal Article Zhang M, Holman CD, Price SD, Sanfilippo FM, Preen DB, Bulsara MK. Comorbidity and repeat admission to hospital for adverse drug reactions in older adults: a retrospective cohort study. BMJ. 2009 Jan 7;338:a2752. DOI: 10.1136/BMJ.a2752. PubMed PMID: 19129307; PubMed Central PMCID: PMC2615549.
    Conference Paper Christensen S, Oppacher F. An analysis of Koza's computational effort statistic for genetic programming. In: Foster JA, Lutton E, Miller J, Ryan C, Tettamanzi AG, editors. Genetic programming. EuroGP 2002: Proceedings of the 5th European Conference on Genetic Programming; 2002 Apr 3-5; Kinsdale, Ireland. Berlin: Springer; 2002. p. 182-91.
    Thesis or Dissertation Borkowski MM. Infant sleep and feeding: a telephone survey of Hispanic Americans [dissertation]. Mount Pleasant (MI): Central Michigan University; 2002.
  • American Medical Association (AMA)
  • AMA style is a relatively new method of citation in the medical sciences field. It follows the numerical in-text citation style, with the page number included in parentheses.

    Oxford University Press publishes a style guide to help authors use AMA citation format.

    AMA Citation Style Example

    Category Work Cited
    Book Reed PG, Shearer NB. Nursing Knowledge and Theory Innovation: Advancing the Science of Practice. New York, NY: Springer; 2011:45-47. id=301779. Accessed September 18, 2012.
    Journal Article Watts T. Initiating end-of-life care pathways: A discussion paper. J Adv Nursing. 2012;68(10):2359-2370. DOI: 10.1111/j.1365-2648.2011.05924.x.
    Conference Paper Cronin C. Memoing: An active tool in research. Poster presented at RCN Annual International Nursing Research Conference; April 23, 2012. London, UK. Accessed September 23, 2012.
    Thesis or Dissertation Taylor RL. Downsizing the Dial: The Reinvention of Private Radio in Canada. [Ph.D. thesis]. Burnaby, BC: British Columbia Institute of Technology; 2008
  • Vancouver
  • Vancouver style is a popular form of referencing used in science and medicine. It is developed by the International Committee of Medical Journal Editors (ICMJE). It uses in-text citations that refer to the corresponding entry in the reference list.

    Vancouver Citation Style Example

    Category Work Cited
    Book Simons NE, Menzies B, Matthews M. A Short Course in Soil and Rock Slope Engineering. London: Thomas Telford Publishing; 2001.
    Journal Article Read B. Anti-cheating crusader vexes some professors. Chronicle of Higher Education. 2008;54(25). Available from: [Accessed 18th June 2015].
    Conference Paper Wittke M. Design, construction, supervision and long-term behavior of tunnels in swelling rock. In: Van Cotthem A, Charlier R, Thymus J-F, Tshibangu J-P. (eds.) Eurock 2006: multiphysics coupling and long term behavior in rock mechanics: Proceedings of the International Symposium of the International Society for Rock Mechanics, EUROCK 2006, 9–12 May 2006, Liège, Belgium. London: Taylor & Francis; 2006. p.211–216.
    Thesis or Dissertation Pahl KM. Preventing anxiety and promoting social and emotional strength in early childhood: an investigation of risk factors [dissertation on the Internet]. St Lucia, Qld: University of ​Queensland; 2009 [cited 2017 Nov 22]. Available from:

    Citation Styles For Humanities

    There are four major citation styles for humanities group: MLA, Chicago, Turabian, and Harvard. The Chicago and MLA styles are most commonly used in the humanities field.

  • Modern Language Association (MLA)
  • MLA (Modern Language Association) style is commonly used in the fields of literature, arts, linguistics, etc. The MLA format is a simple one compared to some other styles, which is why students use it more often.

    MLA Citation Style Example

    Category Work Cited
    Book Franzen, Jonathan. The Corrections. Farrar, Straus, and Giroux, 2001.
    Journal Article Zhai, Xiaojuan, and Jingjing Wang. "Improving Relations Between Users and Libraries: A Survey of Chinese Academic Libraries." The Electronic Library, vol. 34, no. 4, 2016, pp. 597-616.
    Conference Paper Lewis, Jack. “Lost Literature: The Social Consequences of Stock Loss.” Proceedings of the International Library Conference, Amsterdam, 13–14 June, edited by W. Oldham, LCP Publications, 2015.
    Thesis or Dissertation Fletcher, Marissa. Influences of Nutrition and Pathogenicity from a Microbial Diet on Immunity and Longevity in Caenorhabditis Elegans. 2012. Massachusetts Institute of Technology, Ph.D. DSpace@MIT,
  • Chicago Manual of Style (CMOS)
  • The Chicago style is typically used in history papers and books. It is published by the Chicago Manual of Style. This style manual includes the following variations:

    • Chicago A: Uses Note Citation style
    • Chicago B: Uses Parenthetical Citation style

    CMOS Citation Style Example

    Category Work Cited in Chicago A Work Cited in Chicago B
    Book Einstein, Albert. The Meaning of Relativity. Princeton: Princeton University Press, 1923. Einstein, Albert. 1923. The Meaning of Relativity. Princeton: Princeton University Press.
    Journal Article Dickstein, Morris. “A Literature of One’s Own: The Question of Jewish Book Awards.” Princeton University Library Chronicle 63, no. 1–2 (Winter 2002): 70–74. Dickstein, Morris. 2002. “A Literature of One’s Own: The Question of Jewish Book Awards.” Princeton University Library Chronicle 63, no. 1–2 (Winter): 70–74.
    Internet Source (website) Marshall, Alex. “Graphic Novel in Running for Man Booker Prize for First Time.” New York Times, July 23, 2018. Marshall, Alex. 2018. “Graphic Novel in Running for Man Booker Prize for First Time.” New York Times, July 23, 2018.
  • Turabian
  • Turabian style resembles Chicago style and is also published by the Chicago Manual Style. Both styles use two variations: Parenthetical and Note style. Turabian style is used in humanities, while parenthetical is utilized in social sciences.

    Turabian Citation Style Examples

    Category Work Cited
    Book Druin, Allison, and Cynthia Solomon. 1996. Designing multimedia environments for children. New York, NY: J. Wiley & Sons.
    Journal Article Villarreal, Mark. 2006. Finding our place: Reconstructing community through oral history. The Oral History Review 33, no. 2. (accessed August 9, 2010).
    Conference Paper Gallegos, Bee, Tammy Allgood, and Karen Godin. 2007. Quarantined: The Fletcher Library game project. Paper presented at the national conference of LOEX, San Diego, CA. May 4.
    Thesis or Dissertation Kimberly Knight, “Media Epidemics: Viral Structures in Literature and New Media” Ph.D. diss., University of California, Santa Barbara, 2011, MLA International Bibliography (2013420395).
  • Harvard
  • Harvard style citation is an informal style of citation, used mostly in economics and other humanities subjects. No official style guide is available, which means there are variations in how it is used.

    According to scholars, the Harvard Style is similar to the American Psychological Association (APA) citation style in the social sciences discipline. A few organizations have published their own guides for this formatting style.

  • Australian Government Publishing Services (AGPS)
  • British Standard Institute
  • Harvard Citation Style Example

    Category Work Cited
    Book Wallace, R. A., and Wolf, A., (2006). Contemporary sociological theory: expanding the classical tradition. 6th ed. Upper Saddle River, N.J.: Prentice-Hall.
    Journal Article Dobson, H., (2006). Mister Sparkle meets the 'Yakuza': depictions of Japan in The Simpsons. Journal of Popular Culture [online]. 39(1), 44–68. [Viewed 5 October 2015]. Available from: DOI: 10.1111/j.1540-5931.2006.00203.x
    Conference Paper Redknap, M., (2004). Viking–age settlements in Wales and the evidence from Llanbedrgoch. In: J. Hines, A. Lane, and M. Redknap, eds. Land, sea and home, proceedings of a conference on Viking–period settlement, July 2001, Cardiff.Leeds: Maney Publishing, pp. 139–175.
    Thesis or Dissertation Tomlinson, S.E., (2009). Understanding the friction between human fingers and contacting surfaces. Ph.D. thesis, University of Sheffield. [Viewed 14 October 2015]. Available from:

    Citation Styles For Social Sciences

    Three citation styles are used in the social sciences: APA, AAA, and APSA. APA citation style is the most popular.

  • American Psychological Association (APA)
  • APA style is a simple citation format and the most commonly used in the social sciences. It was developed by the American Psychological Association to use specifically for psychological and social science research. It follows the parenthetical citation style for the in-text citation.

    APA Citation Style Example

    Category Work Cited
    Book Druin, A., & Solomon, C. (1996). Designing multimedia environments for children. New York, NY: J. Wiley & Sons.
    Journal Article Humphrey, M., & Hourcade, J. J. (2010). Special educators and mathematics phobia: An initial qualitative investigation. Clearing House: A Journal of Educational Strategies, 83(1), 26-30. DOI: 10.1080/00098650903267743
    Conference Paper Gallegos, B., Allgood, T., & Gondin, K. (2007, May). Quarantined: The Fletcher Library Game Project. Paper presented at the national conference of LOEX, San Diego.
    Thesis or Dissertation Thomas, R. (2009). The making of a journalist: The New Zealand way (Doctoral thesis, Auckland University of Technology, Auckland, New Zealand). Retrieved from
  • American Anthropological Association (AAA)
  • The AAA style was created at a meeting of the American Anthropological Association (AAA) in 1929. It is based on the Chicago style in the humanities group and its name has derived from the author-date system.

    AAA Citation Style Example

    Category Work Cited
    Book Bonacich, Edna, with Mark Smith and Kathy Hunt 1999 The Economic Basis of Ethnic Solidarity: Small Business in the Japanese American Community. Berkeley: University of California Press.
    Journal Article Moll, Luis C. 2000 Writing as Communication: Creating Strategic Learning Environments for Students. Theory into Practice 25(3):202-208.
    Conference Paper Poveda, David 2000 Paths to Participation in Classroom Conversations. Paper presented at the 7th International Pragmatics Conference, Budapest, July 9-14.
    Thesis or Dissertation D’Amato, John 1989 “We Cool, That's Why”: A Study of Personhood and Place in a Class of Hawaiian Second Graders. Ph.D. dissertation, Department of Education, University of Hawaii
  • American Political Science Association (APSA)
  • APSA is a Chicago-style citation style used for political science papers. APSA is the least commonly used citation style. The United States Government has provided specific rules for documentation. It follows the parenthetical style of citation in APSA.

    APSA Citation Style Example

    Category Work Cited
    Book North, Douglass, John Wallis, and Barry Weingast. 2009. Violence and Social Orders: A Conceptual Framework for Interpreting Recorded Human History. Cambridge, England: Cambridge University Press.
    Journal Article Blondel, Jean, and Nick Manning. 2002. "Do Ministers Do What They Say? Ministerial Unreliability, Collegial and Hierarchical Governments." Political Studies 50: 455-76.
    Conference Paper Obergefell v. Hodges. 2014. In Identifying Risk - Poor Or Lack Of Documentation And Record Keeping -Perioperative Care Plan.
    Thesis or Dissertation Munger, Frank J. 1955. “Two-Party Politics in the State of Indiana.” Ph.D. diss. Harvard University.

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    How to Choose the Correct Citation Style for Your Paper?

    When students write a research paper for the first time, they face a dilemma: choosing among the various styles of citations. In general, professors specify the style for students writing their first research paper. However, sometimes professors give students the option to choose their own styles.

    Most of them face difficulties choosing a citation style for their papers. But only two main keys will determine which style is best for your paper.

    • It is important to know which academic discipline your subject fits into, like the social sciences, humanities, or the sciences.
    • When conducting your research, be sure to determine which subject you are writing about, such as psychology, computer science, or any other discipline.

    Citation Management Tools

    You can use several tools for automatic citation, but it is important to choose the right one for your needs. For example, LaTex software is designed to be used with document preparation systems in high-level paper settings.

    LaTex is a high-quality typesetting system that's commonly used for document preparation. The software provides many features designed for the production of scientific and technical documents. Some of its citation features are:

    • BiblaTex: It is a complete redesign and re-implementation of the LaTeX bibliography facilities. It provides easier methods for creating and modifying bibliographies, especially when compared to BibTeX.
    • BibTex: It is a reference management software that is used to format a reference list.
    • Natbib: It is a complete solution for customizing citations. It uses both numbered and author-year references.

    Zotero is free and open-source reference management software, like LaTex. Zotero helps you collect, organize, cite, and share your research.

    Mendeley Citation Styles is also a popular reference management software for research students. It's easy to install and use, with plug-ins for BibTex, LibreOffice, and Word.

    Another software, Endnote Citation Styles helps students to create and organize bibliographies and references in research papers. It has a friendly interface that simplifies the task of keeping track of citations.

    These tools are easy to learn and use. Once you get used to them, you'll have no problem formatting your bibliographies.

    If you need any assistance, we are always ready to help. is the ‘write my essay’ service you can trust. We are a legit essay writing service that will provide any assistance you need with your research papers and other academic works.

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    Frequently Asked Questions

    What is the difference between a citation and referencing?

    The citation is included within the paper or text, while the reference is the full bibliographic information of the same citation.

    What is the most common citation style?

    MLA citation style is the most common type of citation style. It is commonly used in humanities and based on the parenthetical citation format.

    What is the difference between Harvard and APA referencing?

    Harvard-style citations are the preferred formatting for academic papers in education and social sciences. APA referencing is often used in scientific studies and papers.

    Which citation style is easiest?

    There are many ways to cite your paper in the APA or MLA format! If you're looking for something quick and easy, consider one of these two styles.

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