Vennard, W. (1968). Singing: The mechanism and the technic / by William Vennard (Rev. ed., greatly enlarged, 5. ed.). Fischer.

Vennard, William. Singing: The Mechanism and the Technic / by William Vennard. Rev. ed., greatly enlarged, 5. ed. New York, NY [u.a.]: Fischer, 1968.

Vennard, William. Singing: The Mechanism and the Technic / by William Vennard. Rev. ed., greatly enlarged, 5. ed. Fischer, 1968.