..
Whilst presumably not mentioning all the chess books the USCF bought
in Serbia.

That's a good point.

How did the USCF continue to import Yugoslav chess books (such as Informants)
during the period of United States economic sanctions against Yugoslavia?


I read something to the effect that the USCF simply continued to receive
these books during the embargo, while not bothering to send payment until
afterward (if at all).