Justin says:

Michael Chabon refers to Joni on page 10, in my copy, just after the section break."

Page 10
Claire had moved out on the thirtieth of April , taking with her all of the Joni Mitchell and the complete soundtrack recording of the dialogue from Zeffirelli's 'Romeo and Juliet,' a four-record set, which she knew by heart.

(Contributed by Justin Rutledge)