It's revealed that Sheldon is now 30 years old, making him around the same age as Howard, who was also said to be 30 in The Recombination Hypothesis (2012).
Raj and Howard talk about Howard being part of Expedition 31. Expedition 31 was actually made up of six astronauts, Oleg Kononenko, André Kuipers, and Don Pettit, who remained on the ISS from Expedition 30. A month into Expedition 31, they were joined by Joseph M. Acaba, Gennady Padalka, and Sergei Revin. Expedition 31 lasted from April 27-July 1, 2012.
Sheldon makes reference to the song "You've Got a Friend in Me" from Toy Story (1995). Laurie Metcalf who plays Mary Cooper, Sheldon's mother, provided the voice of Andy's mom in Toy Story as well as its sequels.