When Walter and Hank are flipping through Gale's notebook, a Far Side cartoon with a "scientists in the laboratory" theme can briefly be seen. Gary Larson is very particular as to when his work is used, but according to creator Vince Gilligan, Larson is a fan of the show.
The scene between Walt and Skyler playing blackjack was an unprecedented 13 pages in the script.
When Walter and Hank are flipping through Gale's notebook, a 2008 Ron Paul for President sticker can briefly be seen on one of the pages.
When Walt is in the bedroom with Hank looking over Gale's Lab Notebook, there are several pages containing Walt Whitman's free-verse poem "When I Heard the Learn'd Astronomer." In the poem, Whitman conveys his belief in the limits of using science to understand nature. Whitman suggests one needs to experience nature for true understanding instead of measuring it. There are several props that suggest Gale was following this advice, including the Telescope in Gale's apartment and the sitting bicycle strapped to the top of his car and also drawn in the lab notebook. This is also counter to Walter White's calculated and scientific approach to life, which can explain the distance between them apart from the professional bond he had with Gale.
Walt's monologue to his lawyer Saul about Gus is reminiscent of Skyler's monologue to her lawyer about Walt.