After discovering the reference to Stephen Foster's "My Old Kentucky Home" in Jerry Keller's "Here Comes Summer" (I have versions of it by Cliff Richard and by the Dave Clark Five), I got thinking about an-other part of the song - the line "I'll meet the gang at Joe's café." (This line doesn't appear in the DC5's version, however.) I'd previously wondered whether this was a reference to Leiber and Stoller's "Smokey Joe's Café" (I have versions of it by the Coasters [although it's credited to the Robins], by Buddy Holly, and by Loudon Wainwright III), but because of how common a name Joe is, I wasn't sure if this was an actual reference or whether it was just a coincidence.
But now, knowing that Jerry Keller included some words and part of the melody of Foster's "My Old Kentucky Home," it seems more likely that he would also include a nod to a more contemporary song.