Periods in Reference List Entries
by Chelsea Lee
APA Style references have four parts: author, date, title, and source, and these parts are separated by periods. This example of a book reference shows the pattern (the periods are highlighted to help you see them):
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Author, A. (2017). Title of book. Publisher Location: Publisher Name. |
Some cases can cause some confusion, however, such as group authors, screen names, and titles ending in punctuation such as question marks. Read on to learn how to handle reference punctuation in those cases.
When the author of a work is a group, add a period after the group name to end the author portion of the reference.
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Community Preventive Services Task Force. (2015). Clinical decision support systems recommended to prevent cardiovascular disease. American Journal of Preventive Medicine, 49, 796–799. http://dx.doi.org/10.1016/j.amepre.2015.03.041 |
Screen Names
When a user has a screen name as well as a real name (as with many social media references), put a period after the closing brackets that enclose the screen name (but do not put a period between the real name and the screen name).
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Stanford Medicine [SUMedicine]. (2012, October 9). Animal study shows sleeping brain behaves as if it's remembering: http://stan.md/RrqyEt #sleep #neuroscience #research [Tweet]. Retrieved from https://twitter.com/SUMedicine/status/255644688630046720 |
Titles Ending in Punctuation
When the title of a work ends with a punctuation mark, such as a question mark or exclamation point, this punctuation mark takes the place of the period that would otherwise be added at the end of the title.
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Millon, T. (2016). What is a personality disorder? Journal of Personality Disorders, 30, 289–306. http://dx.doi.org/10.1521/pedi.2016.30.3.289 |
References Ending in a DOI or URL
One case where you should never add a period is after a DOI or URL. This is to prevent the impression that the period is part of the DOI or URL (which would then prevent it from working).
Do you have other reference-punctuation questions? Leave them as a comment below.
