Big Brother and the Holding Company

A passerby in the Haight to whom Jessica Willamy was holding out a photo of her missing boyfriend was wearing a  T-shirt. (PROSE: Wonderland)

Behind the scenes
The reader is meant to find this occurrence a perfectly plausible splash of local colour, since Janis Joplin, mentioned several times in the book, was the lead singer of Big Brother and the Holding Company. The book doesn't quite make the connection, though.