medimops (.de) - gebrauchte Bücher und Südkorea ist mit in der Auswahlliste (Lieferadresse) - und da es eine deutsche Seite ist, haben sie das gewünschte Buch vielleicht/wahrscheinlich. Viel Glück!

Book Depository was the go-to place but it went out of business at the end of April :-( He can try Betterworldbooks (.com) - (sorry I can't put in the URL -- everytime I do that in an answer or post, italki tells me I've violated community guidelines). All their books are used. He can refine the search to a particular language (all the way at the bottom on the left) So if he's looking for a particular book, he might be out of luck.

Yes I saw that too :-( I will try betterworldbooks. Thank you for the tip! :-)

Hi, I want practice with you