"Busch suggested that Serkin should go to Berlin to study with Ferruccio Busoni (who, as it happens, was a close friend of Isidor Philipp’s). “The next day,” concludes Leonie Gombrich, “father Serkin came, and everything was settled.”"
January 1, 1970
https://en.wikiquote.org/wiki/Ferruccio_Busoni