Skornicka, J. E., & Boltz, E. G. (1938). Trombone or Baritone: A follow up course for individual or like-instrument class instruction / J. E. Skornicka and E. G. Boltz. Rubank.

Skornicka, J. E., and E. G. Boltz. Trombone or Baritone: A Follow Up Course for Individual or Like-instrument Class Instruction / J. E. Skornicka and E. G. Boltz. Miami, Fl.: Rubank, 1938.

Skornicka, J. E., and E. G. Boltz. Trombone or Baritone: A Follow Up Course for Individual or Like-instrument Class Instruction / J. E. Skornicka and E. G. Boltz. Rubank, 1938.