has to be four revolutions PER second.
The Big Bang Theory Season 10, Episode 20
Not under you PER se...
The Big Bang Theory Season 2, Episode 19
As PER your suggestion,
we're hanging out.
The Big Bang Theory Season 4, Episode 5
of 4.6 yoctometers
PER femtosecond.
The Big Bang Theory Season 5, Episode 18
Now, if you assume 15 tampons PER cycle
in a 28-day cycle...
The Big Bang Theory Season 1, Episode 4