Vennard, W. (1968). Singing: The mechanism and the technic / by William Vennard (Rev. ed., greatly enlarged, 5. ed.). Fischer.
Lua i Stíl Chicago (17ú heag.)Vennard, William. Singing: The Mechanism and the Technic / by William Vennard. Rev. ed., greatly enlarged, 5. ed. New York, NY [u.a.]: Fischer, 1968.
Lua MLA (8ú heag.)Vennard, William. Singing: The Mechanism and the Technic / by William Vennard. Rev. ed., greatly enlarged, 5. ed. Fischer, 1968.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.