McDonald Klimek, M., Obert, K. B., & Steinhauer, K. (2005). Estill voice training system. Estill Voice Training Systems International.
Chicago Style (17. basım) AtıfMcDonald Klimek, Mary, Kerrie B. Obert, ve Kimberly Steinhauer. Estill Voice Training System. [Pittsburgh, Pa.]: Estill Voice Training Systems International, 2005.
MLA (9th ed.) AtıfMcDonald Klimek, Mary, et al. Estill Voice Training System. Estill Voice Training Systems International, 2005.
Uyarı: Bu alıntı herzaman %100 doğru olmayabilir..