E' questo il metodo?:
Amsden's Celebrated Practice Duets for Cornets, Clarinets, Baritones, Saxophones, Horns, Bassoons (or any two instruments in the same key, either bass or treble clef, suitable for the single cornet, clarinet, trombone, baritone or saxophone in either clef or any single instrument as well as duet features) [Spiral-Bound][/color][/size][/font]