She was part of the American team at CERN.
The Big Bang Theory Season 10, Episode 24
American woman
The Big Bang Theory Season 3, Episode 12
Kleingast's Field Guide
to North American Insects.
The Big Bang Theory Season 3, Episode 2
Now, hold on.
If she is dating an American...
The Big Bang Theory Season 4, Episode 20
Ever since I saw Pretty in Pink,
I've wanted to go to an American prom.
The Big Bang Theory Season 8, Episode 8