Using APA formatting, how do you structure an in-text citation that is possessive?

I’m wondering if anyone knows the way to format a citation, APA style, if the author’s name is being written as possessive. I’ve looked through a variety of APA formatting guides, but haven’t managed to dig anything up. Is there a proper way to go about citing a source like that, or should the sentence just be restructured as to avoid the issue all together?

For some context:

Proper citation: (Hill, 1974) or, if the name Hill is used in the sentence, it is followed with (1974).

Example sentence: “Hill’s experiment showed that…”