Booth is reading an issue of Green Lantern when he's in his bathtub. David Boreanaz does the voice of Green Lantern in Justice League: The New Frontier (2008).
The three letters Cam describes to Zack in the hospital are the Greek alphabet letters 'pi', 'beta' and 'alpha', in that order.
The 2007-2008 Writer Guild of America strike which caused a four-month hiatus also caused Season 3 to be only 15 episodes.
By coincidence, both this episode and an episode of the CBS sitcom The Big Bang Theory (2007) ("The Tangerine Factor"), which aired on the same night, May 19, 2008, reference Schrödinger's cat.