Appelman, D. R. (1986). The science of vocal pedagogy: Theory and application (1st Midland book ed.). Indiana University Press.
Lua i Stíl Chicago (17ú heag.)Appelman, D. Ralph. The Science of Vocal Pedagogy: Theory and Application. 1st Midland book ed. Bloomington: Indiana University Press, 1986.
Lua MLA (9ú heag.)Appelman, D. Ralph. The Science of Vocal Pedagogy: Theory and Application. 1st Midland book ed. Indiana University Press, 1986.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.