LibGuides: Citing sources according to APA guidelines: 4.3 Reference works: Entry in a dictionary ǀ Entry in an encyclopedia ǀ Wikipedia article

4.3 Reference works

On this page:

•	Entry in an online dictionary (with retrieval date)	•	Entry in an online encyclopedia (individual author)
•	Entry in a print dictionary	•	Wikipedia article

In the reference list

Merriam-Webster. (n.d.). Paradox. In Merriam-Webster.com dictionary. Retrieved August 14, 2021, from https://www.merriam-webster.com/dictionary/paradox

American Psychological Association (n.d). Gauss-Markov theorem. In APA dictionary of psychology. Retrieved April 12, 2022, from https://dictionary.apa.org/gauss-markov-theorem

Begin the reference with the organizational author.
Merriam-Webster’s Dictionary and APA Dictionary of Psychology are continuously updated. If a date for the entry is not indicated, use “n.d.” (for “no date”) instead of a publication year.
List the entry title.
Provide the source title (in italics), preceded by “In” (not in italics). Capitalize the first word of the title and any proper nouns.
End the reference with the URL. Since both dictionaries are not archived, include a retrieval date before the URL.
Do not include a period after the URL.

In the text

Parenthetical citations: (Merriam-Webster, n.d.; American Psychological Association, n.d.)

Narrative citations: Merriam-Webster (n.d.) and American Psychological Association (n.d.)

In the reference list

American Psychological Association. (2015). Mood induction. In APA dictionary of psychology (2nd ed., p. 667).

Begin the reference with the organizational author, followed by the publication year.
List the entry title.
Provide the source title (in italics), preceded by “In” (not in italics). Capitalize the first word of the title and any proper nouns.
After the title, provide the page number or range of the entry in parentheses (not in italics). Separate page numbers with an en dash (e.g., pp. 566–557). If the entry is a 2nd, subsequent, or revised edition, let the edition information precede the page number or range.

In the text

Parenthetical citation: (American Psychological Association, 2015)

Narrative citation: American Psychological Association (2015)

In the reference list

Steup, M., & Neta, R. (2020). Epistemology. In E. N. Zalta (Ed.), The Stanford encyclopedia of philosophy (Fall 2020 ed.). Stanford University. https://plato.stanford.edu/archives/fall2020/entries/epistemology

Begin the reference with the name(s) of the author(s) of the entry, followed by the publication year.
List the entry title.
Then give the initial(s) and surname(s) – in that order – of the editor(s) of the encyclopedia. Add the abbreviation “Ed.” after the editor’s last name in parentheses. In the case of multiple editors, add “Eds.” after the last editor’s name. Precede the name of the (first) editor by “In.”
Provide the title of the encyclopedia (in italics). Capitalize the first word of the title and any proper nouns. Notice the comma between the editor’s surname and the title of the encyclopedia.
If the encyclopedia is a 2nd, subsequent, or revised edition, provide the edition information in parentheses (not in italics).
Then, provide the name of the publisher.
End the reference with a direct link to the entry. Because The Stanford Encyclopedia of Philosophy is archived, a retrieval date is not needed.
Do not include a period after the URL.

In the text

Parenthetical citation: (Steup & Neta, 2020)

Narrative citation: Steup and Neta (2020)

In the reference list

Begin the reference with the title of the article, as there is no known author.
Give the exact date.
Provide the title of the source (in italics), preceded by “In.”
End the reference with the URL of the article. Provide an archived version of an article so that readers can retrieve the version you used. Access the archived version on Wikipedia by selecting “View history” and then clicking on the time and date of the version you used.
Do not include a retrieval date.
Do not include a period after the URL.

In the text

Parenthetical citation: (“Prisoner’s dilemma,” 2022)

Narrative citation: “Prisoner’s dilemma” (2022)

Please note If you are a student, ask your professor if Wikipedia is an appropriate source to use in your paper or thesis.