Matt's quotation of "compare me to something and tell me what I am like..." comes from The Gospel of Thomas, a non-canonical gospel not included in the Bible.
The mantra "LET US SMOKE," seen on a sign in Patti's office, comes from the G.R.'s Christmas Day slideshow in the book, as do the sayings "WE WON'T LET THEM FORGET," seen when Kevin distributes the whistles, and "IT WON'T BE LONG NOW," seen behind Laurie when Matt tries to hold a prayer session.
When Patti and Laurie drive to Neil's (and possibly Patti's) house the car stereo plays "What A Fool Believes" by The Doobie Brothers.
The clipboard held by the ATFEC employee in the final scene lists, among other cults, a group called "Apollo's Army."