
was an obvious REFERENCE
The Big Bang Theory Season 7, Episode 3

The Star Trek REFERENCE
and the play on words...
The Big Bang Theory Season 2, Episode 22

...you might wanna skip the REFERENCE
to bowel movements.
The Big Bang Theory Season 1, Episode 1

In REFERENCE to a database
much larger than anything
I know of in the park.
Westworld Season 2, Episode 4

What REFERENCE?
The Big Bang Theory Season 8, Episode 19