- E-bookThe Musical Myths and Facts (Vol. 1&2)Carl Engel
- E-bookMusical Myths and Facts, Volume I (of 2)Carl Engel
- E-bookMusical InstrumentsCarl Engel
- E-bookMusical Myths and Facts (Vol. 1&2)Carl Engel
- E-bookMusical Myths and Facts, Volume II (of 2)Carl Engel
- E-bookMusical InstrumentsCarl Engel
- E-bookMusical InstrumentsCarl Engel