Q. If a run-in quotation ends with a question mark or exclamation point, is a period needed following the parenthetical source? For example: The girl in the novel asked, “Where’s Toto?” (Baum 1939) Could you also direct me to the section and examples in CMOS 17? Thanks in advance for the help!
A. Yes, you need to add a period after the closing parenthesis, but only if the quotation is presented in line with the rest of the text (as in your question).
For example, you might quote Dorothy asking the Lion (capitalized in the original) not to bite her dog: “Don’t you dare to bite Toto!” (Baum 1900, 67). Note that we’re referring to the original 1900 edition of the L. Frank Baum classic (published by the George M. Hill Company). And note the period after the parenthetical citation.
But if you present the quotation as a block, there’s no period after the source:
“Don’t you dare to bite Toto! You ought to be ashamed of yourself, a big beast like you, to bite a poor little dog!”
“I didn’t bite him,” said the Lion, as he rubbed his nose with his paw where Dorothy had hit it.
“No, but you tried to,” she retorted. “You are nothing but a big coward.”
“I know it,” said the Lion, hanging his head in shame; “I’ve always known it. But how can I help it?” (Baum 1900, 67)
See CMOS 13.69 and 13.70, respectively. And don’t forget about search. If you enter the words “source period parentheses” in the search box at CMOS Online, you should get those paragraphs among the top results.