APA Citation Style – A Quick Guide

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Research papers and academic publications often follow a standard method of citing their source materials. The APA citation style is one of the styles used to acknowledge all the research sources used to generate the findings of a case study. The rules of APA citation style are defined in the APA Handbook, used by researchers worldwide.1

APA Citation – In a Nutshell

  • APA citation style is a benchmark in scientific writing.
  • Research is the force that drives innovation; thus, the ideas presented in a research paper should be coherent and verifiable.
  • The citation style stipulates a standard type of writing citations in research.
  • It provides flow in a research paper, as it follows a format that is used universally.
  • APA citation style ensures consistency.

Definition of APA citation

APA citation refers to the American Psychological Association’s stipulations for correctly framing and citing references. References or sources, in this case, are books, periodicals, journals, videos, or audio files. Researchers often use other people’s work as resources to study the subject. Failure to cite your sources can be regarded as plagiarism, which may affect the credibility of your findings.2

Inserting an APA citation in a text

In-text citations are inserted in the body of a research paper to show the source of the ideas expressed. Citations may include statements or figures to support a claim. They are used in the research text to guide readers to the primary resource used for further information on the reference page. In-text citation in APA style follows the author-date format; the author’s last name and the publication date are separated by a comma.3

Parenthetical vs. narrative citation

APA citations can be parenthetical or narrative.

  • Parenthetical citations include the author’s name and year of publication, both encased in parentheses.


(Jefferson, 2019).

  • Narrative citations encase only the year in parentheses, while the author’s name is part of the sentence.4


Jefferson (2019) suggests…

Multiple authors and organizations

Any comprehensive research undertaking uses multiple sources of information in different forms. APA citation proposes guidelines on how to cite multiple authors and organizations.

Parenthetical and narrative citations may be used interchangeably in APA citations as follows:

No. of Authors Narrative Citation Parenthetical Citation
One author Jefferson (2019) (Jefferson, 2019)
Two authors Bryant and Jefferson (2019) (Bryant & Jefferson, 2019)
Three and more Jefferson et al. (2019) (Jefferson et al., 2019)
Organization NASA (2019) (NASA, 2019)

No author, publication date, or page number

Numerous sources can be used for research. Many researchers gravitate toward sources with known authors and publication dates. However, some of these details may be unavailable. In APA citation, missing information is presented as shown below:

Missing Information How to Cite Citation Example
Author Use the title of the source (The Odyssey, 2019)
Date Label as "n.d" to stand for 'no date.' (Jefferson, n.d.)
Page number Don't write the page number or use a substitute locator (Jefferson, 2019) or (Jefferson, Chapter 5, 2019)

Generating the reference list in APA citation style

APA citation references consist of more details about the in-text citations used in the research material and other sources. They are usually made up of:

  • Authors name
  • Title
  • Source
  • Publication date


Harden, J. (2014). The farmer’s guide for winter: A definitive guide (3rd ed.). McGraw Hill.

In some instances, you may include more information such as locations to help readers find the original sources.

References with missing information

Some sources may have missing elements like titles, authors, or dates. The APA citation defines the following actions for missing information:

Missing Information How to Cite Reference Style
Author Start with the title of the source Title. (Date). Source
Date Label as 'n.d.' for 'no date' Author. (n.d.). Title. Source
Title Write the work within square brackets Author. (Date). [Description]. Source.

Formatting the reference page in APA citation style

This is the last page after the research text. You mention all the sources you have used in your research. The reference list in APA citation style is structured as follows:

Heading: Use a boldface font to label the page on the first line. The label here is ‘References’ and centered.

List your references in alphabetical order. The first element, i.e., the author’s last name, is used in the APA citation style.

Use the following formatting rules:

  • Double-spacing throughout the page
  • ½ inch hanging indent
  • Use a readable font such as Arial or Times New Roman
  • Indicate the page number in the right section of the header5


Some research sources may have no known author. Start by finding out if the work was published by an organization or government. Such sources may not have a specific author, as they are published as institutional releases. Mention the name of the country or institution in the in-text citation and reference list.


  • Smart machines can be used to solve a large proportion of human problems for both personal and professional needs (Google, 2017).

All the items on the reference list should be available and findable to the readers of the research paper. Phone calls, interviews, seminars, and other forms of personal communication are not mentioned on the reference list, as they are inaccessible. However, they can be added as in-text citations with the description “personal communication” and the long-form date.


  • Interest rates affect portfolios with a high bond-to-stock ratio (E. G. White, personal communication, July 23, 2016).

The reference page in APA citation style is the list of sources used in your research. This includes magazines, periodicals, video sources, and books. Information from personal communication is not included as it cannot be tracked. The reference list is introduced on a new page at the end of the main research text.6

The initials et al. are used where a source has more than two authors. A publication with two authors can be cited using the authors’ last names. For instance: (Parker & Jill, 2022), however, if there are three or more authors, we use et al. and the first author’s name.


  • (Parker, et al., 2019).

This short form shows that there are several authors whose names can be seen on the reference page.

The author-date citation in APA is used when writing in-text citations. It uses the author’s last name followed by the year the source was published.


  • (Smith, 2020).

Sometimes, you may provide additional information, such as page numbers.7


1 USC Libraries. “APA Style 7th Edition: Citing Your Sources.” October 26, 2022. https://libguides.usc.edu/APA7th.

2 Study.com “APA Citation: Formats & Examples.” August 5, 2020. https://study.com/academy/lesson/how-to-format-apa-citations.html.

3 University Libraries. “APA Citation Guide (7th Edition): In-Text Citation.” University of Nevada, Reno.  Accessed October 28, 2022. https://guides.library.unr.edu/apacitation/in-textcite.

4 University Writing & Speaking Center. “APA 7 in-text citations.” University of Nevada, Reno. Accessed October 28, 2022. https://www.unr.edu/writing-speaking-center/student-resources/writing-speaking-resources/apa-7-in-text-citations.

5 Betts, Jennifer. “APA Reference Page Examples and Format Guide.” Bibliography.com. Accessed October 28, 2022. https://www.bibliography.com/apa/apa-reference-page-examples-and-format-guide/.

6 Purdue Online Writing Lab. “Reference List: Basic Rules.” Purdue University. Accessed October 28, 2022. https://owl.purdue.edu/owl/research_and_citation/apa_style/apa_formatting_and_style_guide/reference_list_basic_rules.html.

7 American Psychological Assosication. “Author-Date Citation System.” APA Style. September, 2019. https://apastyle.apa.org/style-grammar-guidelines/citations/basic-principles/author-date.