The forthcoming George and Ira Gershwin Critical Edition of "An American in Paris" suggests that the iconic taxi horn parts played by orchestras since the 1940's is not what Gershwin intended.
From the Umich page that discusses this... defines notes as A3 D5 Bb4 Ab4 from left to right. That Bb is pretty sharp! smtd.umich.edu/ami/gershwin/?p=715
Tchaikovsky: I made the cannon an instrument
Gershwin: Hold my beer
but recently score notes were found from the recording session I'm back in 2018 couple years after this show was produced
From the Umich page that discusses this... defines notes as A3 D5 Bb4 Ab4 from left to right. That Bb is pretty sharp! smtd.umich.edu/ami/gershwin/?p=715
Is this real? Check the upload date?
A bit daft to use letters, surely, knowing that they were bound to confuse....
I would have used names of an ornithological variety