APA (7 वां संस्करण) प्रशस्ति पत्र

McDonald Klimek, M., Obert, K. B., & Steinhauer, K. (2005). Estill voice training system. Estill Voice Training Systems International.

शिकागो शैली (17वां संस्करण) प्रशस्ति पत्र

McDonald Klimek, Mary, Kerrie B. Obert, और Kimberly Steinhauer. Estill Voice Training System. [Pittsburgh, Pa.]: Estill Voice Training Systems International, 2005.

एमएलए (9वां संस्करण) प्रशस्ति पत्र

McDonald Klimek, Mary, et al. Estill Voice Training System. Estill Voice Training Systems International, 2005.