Pete Ross mentions an internship with Mayor Siegel, the name being a throwback to one of the original creators, Jerry Siegel.
Another reference to Clark Kent's origins: Chloe Sullivan states that most men are from Mars but Clark is from a whole other galaxy.
There is a mention of Lex Luthor's full first name, 'Alexander'.
There are many references to Walt Whitman poems in this episode. First, Lionel Luthor reads of the first few lines from Whitman's Song of Myself. Towards the end, Lex is seen carrying the book titled 'Leaves of Grass' by Walt Whitman.