There are several different types of citation formats (also called citation styles or reference systems). The citation format you use influences how your citations appear in your text and how your reference list looks. Some academic disciplines have traditionally preferred specific citation formats. Ask your supervisor whether that's the case for your field.
Broadly speaking, citation formats can be divided into two types:
"Author-date"-formats is characterized by the in-text references containing the author and the year of publication.
Numerical formats are set up so your sources are numbered. Depending on the citation format one number could refer to a specifc reference throughout your paper, or in some formats a new number is used every time you cite something, whether its a new reference or one that you have referenced before.
Some of the most commonly used citation formats are APA (American Psychological Association), MLA (Modern Language Association), Chicago, IEEE (Institute of Electrical and Electronics Engineers), Harvard, and Vancouver.
These will all be described in more detail below.
Author-date
APA is short for the American Psychological Association, who manages and updates the format. APA is primarily used within the social sciences and humanities, but has also been adopted elsewhere. It is one of the most widely used citation formats.
Find the official guidelines for using APA here: The Official Style Blog
Examples:
In-text citation:
In the 'References':
Author-date
MLA is short for the Modern Language Association, who manages and updates the format. MLA is primarily used within the humanities and social sciences. MLA categorized as "author-date" here although "author-title" probably would be more apt, since the title of the source is prioritized in the bibliography, and the year is not mentioned in the in-text citations.
Find the official guidelines for using MLA here: MLA Style Center
Examples:
In-text citation:
“It seems that highly cited papers may not make direct contributions to scholarship in a way that is proportional to their citation counts” (Thelwall 10).
Prior research indicates that highly cited articles are often included as a form of agenda-setting (Thelwall).
In the 'Works Cited':
A book:
Neville, Colin. The Complete Guide to Referencing and Avoiding Plagiarism. 2nd ed., Open University Press, 2010.
A book chapter:
Neville, Colin. “The ‘what’ and ‘when’ of Referencing”. The Complete Guide to Referencing and Avoiding Plagiarism, 2nd ed., Open University Press, 2010, pp. 14–27.
Numerical
The Chicago-style is managed by the University of Chicago and consists of two variations, one uses author-date and another using the numerical system. Author-date is often used within the humanities, while the numerical is used within the social sciences. The difference is mainly in the in-text citations, while the reference list looks the same. Do note though, that it is called a bibliography in the numerical variation and references in the author-date version.
In the numerical version, a footnote is created where a longer reference can be found. The first time a work is cited, the reference in the footnote will be the same as in the bibliography, while a shortened version will be used subsequently.
Find the official guidelines for using Chicago here: Chicago Style Quick Guide
Examples:
In-text citation:
“It seems that highly cited papers may not make direct contributions to scholarship in a way that is proportional to their citation counts”¹
Prior research indicates that highly cited articles are often included as a form of agenda-setting¹
In the footnote:
¹Mike Thelwall, “Are Classic References Cited First? An Analysis of Citation Order within Article Sections”, Scientometrics 120, no. 2 (1. august 2019): 10, https://doi.org/10.1007/s11192-019-03142-8.
²Thelwall, “Are Classic References Cited First?”
In the 'Bibliography':
A book:
Neville, Colin. 2010. The Complete Guide to Referencing and Avoiding Plagiarism. 2nd ed. Maidenhead: Open University Press.
A book chapter:
Neville, Colin. 2010. “The ‘what’ and ‘when’ of Referencing”. In The Complete Guide to Referencing and Avoiding Plagiarism, 2nd ed., 14–27. Maidenhead: Open University Press.
Author-date
The Chicago-style is managed by the University of Chicago and consists of two variations, one uses author-date and another using the numerical system. Author-date is often used within the humanities, while the numerical is used within the social sciences. The difference is in the in-text citations, while the reference list looks the same. Do note though, that it is called a bibliography in the numerical variation and references in the author-date version.
Find the official guidelines for using Chicago here: Chicago Style Quick Guide
Examples:
In-text citation:
“It seems that highly cited papers may not make direct contributions to scholarship in a way that is proportional to their citation counts” (Thelwall 2019, 10)
Prior research indicates that highly cited articles are often included as a form of agenda-setting (Thelwall 2019).
In the 'References':
A book:
Neville, Colin. 2010. The Complete Guide to Referencing and Avoiding Plagiarism. 2nd ed. Maidenhead: Open University Press.
A book chapter:
Neville, Colin. 2010. “The ‘what’ and ‘when’ of Referencing”. In The Complete Guide to Referencing and Avoiding Plagiarism, 2nd ed., 14–27. Maidenhead: Open University Press.
Author-year
Unlike most other citation formats, Harvard is not associated with a specific institution or organization that sets guidelines and update standards. Instead, it is more of a general designation for the “author-year” type when used within the natural and social sciences.
Find a more general guide for using Harvard here: Mendeley's Harvard guide.
Examples:
In-text citation:
“It seems that highly cited papers may not make direct contributions to scholarship in a way that is proportional to their citation counts” (Thelwall, 2019, p. 10).
Prior research indicates that highly cited articles are often included as a form of agenda-setting (Thelwall 2019).
As Thelwall (2019) emphasizes…
In the 'References':
A book:
Neville, C. (2010) The Complete Guide to Referencing and Avoiding Plagiarism. 2nd edn. Maidenhead: Open University Press.
A book chapter:
Neville, C. (2010) ‘The “what” and “when” of referencing’, in The Complete Guide to Referencing and Avoiding Plagiarism. 2nd edn. Maidenhead: Open University Press, pp. 14–27.
Numerical
IEEE is short for Institute for Electrical and Electronics Engineers, which manages and updates the standard. IEEE is primarily used within engineering, computer science and similar fields. In the citation, a number is given that refers to a specific source. In the bibliography, sources are sorted by this number, rather than the author’s name, which is the case with the author-year types.
Find the official guidelines for using IEEE here: IEEE Style Manual
Eksempler:
In-text citation:
“It seems that highly cited papers may not make direct contributions to scholarship in a way that is proportional to their citation counts” [1, p. 10]
Prior research indicates that highly cited articles are often included as a form of agenda-setting [1]
In the 'References':
A book:
[1] C. Neville, The Complete Guide to Referencing and Avoiding Plagiarism, 2nd ed., Maidenhead: Open University Press, 2010.
A book chapter:
[1] C. Neville, “The ‘what’ and ‘when’ of referencing”, in The Complete Guide to Referencing and Avoiding Plagiarism, 2nd ed., Maidenhead: Open University Press, 2010, pp. 14–27.
Numerical
The Vancouver format is maintained and updated by the NLM, which is the United States National Library of Medicine. The Vancouver system is mainly used within the medical fields. In the citation, a number is given that refers to a specific source. In the bibliography, sources are sorted by this number, rather than the author’s name, which is the case with the author-year types.
Find the official guidelines for using Vancouver here: Citing Medicine
Examples:
In-text citation:
“It seems that highly cited papers may not make direct contributions to scholarship in a way that is proportional to their citation counts” (1, p. 10)
Prior research indicates that highly cited articles are often included as a form of agenda-setting (1)
In the 'References':
A book:
(1) Neville C. The Complete Guide to Referencing and Avoiding Plagiarism, 2nd ed. Maidenhead: Open University Press, 2010.
A book chapter:
(1) Neville C. The “what” and “when” of referencing. In: The Complete Guide to Referencing and Avoiding Plagiarism. 2nd ed. Maidenhead: Open University Press; 2010. p. 14–27.
Ibid. is an abbreviation of the Latin word ibidem, meaning "in the same place". Ibid. is used in in-text citations when referencing the same work multiple times in a row.
Using ibid. can improve the reading experience, especially in author-date citation formats where the in-text citations can be lengthy. However you should be aware that in recent years, many citation formats have moved away from using ibid.
Both APA and MLA does not allow the use of ibid., while Chicago recommends against using it.
The guide on this page is merely an overview of the differences between citation formats. Below, you will find links to more detailed guides for each citation format.
The official guidelines can be found at:
The Official Style Blog by the American Psycholgical Association
The official guidelines can be found at:
MLA Style Center by the Modern Language Association
The official guidelines can be found at:
Chicago Style Quick Guide by the University of Chicago
The Harvard format does not have an official style guide by a governing institution or organization.
For a more general guide to using Harvard use this link from the reference management tool Mendeley's guide.
The official guidelines can be found at:
IEEE Style Manual by the Institute for Electrical and Electronics Engineers
The official guidelines for using Vancouver is described in Citing Medicine 2nd ed., see the link below
Citing Medicine published by the United States National Library of Medicine
