In a works-cited-list entry, if a URL ends with a question mark, should a period follow?
If the last element of a works-cited-list entry is a URL ending in a question mark, a period should follow the URL:
Krugman, Paul. “Bubble, Bubble, Fraud and Trouble.” The New York Times, 29 Jan. 2018, www.nytimes.com/2018/01/29/opinion/bitcoin-bubble-fraud.html?.
Note, however, that the rule differs for the title of a work ending in a question mark or exclamation point at the end of a sentence. See our post on punctuation with titles.