
It's recommended by
the Department of Homeland Security.
The Big Bang Theory Season 2, Episode 1

...but the Pasadena Police Department
doesn't have jurisdiction in Pandora.
The Big Bang Theory Season 4, Episode 19

I got a buddy over at
the Department of Defense.
The Big Bang Theory Season 3, Episode 13

and the Geology Department.
The Big Bang Theory Season 5, Episode 1

As many of you
in the Physics Department know...
The Big Bang Theory Season 3, Episode 1