Hello Guys, I am new in this forum, I recently bought a Alfred Arnold Bandoneon-Concertina 128 tones. I am a beginner in this instrument . I am interested in tango music. I was told that 142 tones were appropriated , but 128 tones are " studio bandoneon" .....instructors in america will be difficult to find, I wonder where can I find material to study 128 concertina layout?....I will really appreciated your help.