Forrás: Method for Slide Trombone in B-flat. to point out the little things that I had ignored or didn't play correctly. Otto Langey.
Fordítás: Módszer Slide harsona B-dúr. Ottó Langey. Harsona kotta. Fejlett. Method for Slide Trombone in B-flat composed by Otto Langey. 1851-1922.