
That's CLASSIFIED.
The Big Bang Theory Season 2, Episode 22

It's CLASSIFIED.
If we tell anyone we'd get in trouble.
The Big Bang Theory Season 10, Episode 15

It's a secure lab
in a CLASSIFIED facility,
The Big Bang Theory Season 10, Episode 23

Classified, Leonard.
The Big Bang Theory Season 2, Episode 22

Oh, the project is CLASSIFIED,
I can't tell you.
The Big Bang Theory Season 10, Episode 19