Howard and Raj remain in a fight. Sheldon prepares for Amy's birthday.
The Big Bang Theory (season 11) - Wikipedia
The Big Bang Theory' Season 11 Episode 18 Recap: Penny Envisions a New Career
The Big Bang Theory Recap Season 11 Episode 20
The Big Bang Theory' Season 11, Episode 16 recap: The gang welcomes its newest member
Recap of The Big Bang Theory Season 11 Episode 21
The Big Bang Theory' Season 11 Episode 15 Recap: Sheldon Finally Realizes How Selfish He's Been
The Opening Night Excitation, The Big Bang Theory Wiki
Big Bang Theory recap: Season 11, Episode 10
Big Bang Theory recap: Season 11, Episode 21
The Big Bang Theory' Book Revelations: On Set Secrets, More