Merle finds a car and blasts music inside of it, attracting a horde of walkers around the vehicle. One of the zombies that the music attracts is recognizable as being that film's aptly named ‘Plaid Shirt Zombie’, who is seen at the deserted airport hangar.
The passage Carol reads to the kid before the knives come out is from The Adventures of Tom Sawyer by Mark Twain, where Tom and Becky Thatcher are lost in a cave, with little hope of rescue and a candle that's burning down to almost nothing.
Lizzie Samuels was seen talking to Hershel Greene about Tom Sawyer. She was saying that she was enjoying it, but Carol would never get to finish it, but Hershel insisted that Carol would give it her best try.