APA (American Psychological Association) style is commonly used for citing references in science and social science papers, including research papers. This style guide is most frequently used in publications from the American Psychological Association, the social sciences, education, nursing, and business.
The key aspects of APA style are in-text citations and a reference list at the end of the paper that provides full details of the sources cited. An APA reference citation includes information such as the author, date of publication, title, and source of the work. Both the in-text citation and reference list entry are required for proper APA formatting.
In-text citations are placed within sentences and paragraphs to show credit to the original source of information or ideas. These citations include the author’s last name and year of publication, for example (Smith, 2020). Page numbers must also be included for direct quotes. The reference list is placed at the end of the paper, organized alphabetically by the last name of the first author of each source.
Here is an example of an APA citation for a journal article from a single author:
Smith, J. (2020). Title of article. Journal Title, Volume(Issue), page range. https://doi.org/xx.xxx/yyyy
And here is an example reference list entry:
Smith, J. (2020). How to correctly cite sources in APA style. Studies in Citation Formatting, 12(3), 456-478. https://doi.org/10.4135/journal.4563452
For sources with two authors, cite both last names in every in-text citation, connected by an ampersand (&). The reference list entry lists the last names in the same order as they appear in the source. For example:
(Jones & Smith, 2022)
Jones, A., & Smith, B. (2022). Article title. Journal Title, etc.
For three to five authors, cite all authors’ last names at the first mention in-text, and use et al. thereafter. List all authors in the reference list entry. For example:
First mention: (Johnson, Williams, Miller, Davis, & Wilson, 2023)
Subsequent mentions: (Johnson et al., 2023)
Johnson, A., Williams, B., Miller, C., Davis, D., & Wilson, E. (2023). Article title. Journal Title, etc.
When a source has six or more authors, always cite the first author followed by et al. in every in-text citation. List the first six authors followed by ellipses (…) then the last author’s name in the reference list entry. For example:
(Smith et al., 2021)
Smith, A., Jones, B., Davis, C., Miller, D., Wilson, E., & Johnson, F….Zoe, P. (2021). Article title. Journal Title, etc.
For sources with no author listed, use the title or a shortened version as the in-text citation. Use the full title (or shortened version if overly long) in double quotation marks as the first element of the reference list entry. Some examples:
In-text: (“APA Style Citation Guide”, 2020)
Reference list: “APA Style Citation Guide.” (2020). Retrieved from https://libguides.example.edu/CitationHelp
In-text: (Harvard Referencing Guide, 2021)
Reference list: Harvard Referencing Guide. (2021, March 15). Retrieved from https://libguides.example.edu/HarvardGuide
When citing books in APA style, only the author’s name and year of publication are included in the in-text citation. In the reference list, include the author, year, title, publisher, and DOI or URL if the source is electronic. For example:
In-text: (Anderson, 2020)
Reference list:
Anderson, J. (2020). How to write a great research paper. Example Publisher.
When citing chapters from edited books, include the chapter author(s) and year in the in-text citation. In the reference list entry, include the chapter author(s), chapter title, book editor(s), book title, publisher, and page range. For example:
In-text: (Smith, 2022)
Reference list:
Smith, J. (2022). Chapter title. In A. Editor & B. Editor (Eds.), Book title (pp. 100-150). Example Publisher.
Proper citing of web pages and online sources follows a similar format. Cite the author and year in-text, and include the required reference list elements of author, date, title, source/website name, and URL. Here are some examples:
In-text: (Example Website, 2021)
Reference list:
Example Website. (2021, May 5). Page or post title. Retrieved Date, from http://www.examplewebsite.com/page-url
In-text: (Doe, 2020)
Reference list:
Doe, J. (2020, July 15). Article or page title. Example Online Newspaper. https://www.example-news.org/article-url
APA citation style ensures proper credit is given to original sources, avoids plagiarism, and allows readers to locate the cited sources. Following the general format for both in-text citations and reference list entries is essential for proper APA formatting. Consult the latest APA Publication Manual for any unclear citation situations.