Periods are punctuation marks used to separate sentences or elements of reference lists. Use a period in the following instances.
Example: Johnson (1998) claimed that he had cured cancer.
Example: It was clear that Hong Kong had been culturally colonized by the West (Gouper & Finn, 1987).
Example: Boomer and Watts (2003) insisted that "there was little that could save NATO in its current state" (p. 54).
Example: Vonnegut (1965) believed that
All time is all time. It does not change. It does not lend itself to warnings or explanations. It simply is. Take it moment by moment, and you will find that we are all, as I've said before, bugs in amber. (p. 65)
Example: Smith, J. (2009). Best book ever. New York, NY: HarperCollins.
Refer to section 4.02 of the APA manual for more information about the use of periods.
Periods are not necessary when using acronyms.
Example: My instructor told me to consult my A.P.A. manual.