"Why Sheldon Cooper, PhD...
The Big Bang Theory Season 3, Episode 15
I have a PhD in astrophysics.
The Big Bang Theory Season 10, Episode 18
Sorry. I didn't get my PhD
in quitting.
The Big Bang Theory Season 11, Episode 15
I'm getting my PhD.
The Big Bang Theory Season 4, Episode 24
If you could run out and get a PhD,
that might make her like you.
The Big Bang Theory Season 8, Episode 23