I'm surprised you know that REFERENCE.
The Big Bang Theory Season 8, Episode 19
Yeah, for future REFERENCE,
that's a while.
The Big Bang Theory Season 7, Episode 15
If you ever need a REFERENCE
or anything, just let me know.
The Big Bang Theory Season 9, Episode 23
...you'd be in a non-inertial
REFERENCE frame and would...
The Big Bang Theory Season 1, Episode 3
That is a cleverly veiled REFERENCE
to Howard's lifelong obsession...
The Big Bang Theory Season 6, Episode 9