Dr. Linkletter tells Sheldon "Scientist who pursue little green men get laughed at" could be a reference to The Big Bang Theory (2007) - The Decision Reverberation (2019), which sees Sheldon friend Raj gets mocked for believing in aliens after someone questions him at the planetarium he worked at about his belief and he says as a scientist he can't definitively say one way or another and it snowballs to people thinking he said he believed in aliens and making fun of him.