A sign in front of a shop reads "Browse through our bra barrel!"
Burns' command that Homer "Quit cogitating, Steinmetz" refers to Charles P. Steinmetz, one of the most important contributors to the development and adoption of alternating current as an electrical engineer at GE. He died in 1923.
Krusty's line, "I knew my kind wasn't welcome here", is likely a reference to his background, as many country clubs historically didn't allow Jewish members.
Maggie only appears at the end of this episode, however, she also appears in a deleted scene.