Christy, V. A. (1990). Foundations in singing: A basic textbook in vocal technique and song interpretation (2nd ed. medium-high voice ed.). W.C. Brown.
Chicago-referens (17:e uppl.)Christy, Van Ambrose. Foundations in Singing: A Basic Textbook in Vocal Technique and Song Interpretation. 2nd ed. medium-high voice ed. Dubuque, Iowa: W.C. Brown, 1990.
MLA-referens (9:e uppl.)Christy, Van Ambrose. Foundations in Singing: A Basic Textbook in Vocal Technique and Song Interpretation. 2nd ed. medium-high voice ed. W.C. Brown, 1990.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.