1. Bady, S. L. (1985). The voice as a curative factor in psychotherapy. Psychoanalytic Review, 72, 479–490.
2. Bernstein, D. A., & Borkovec, T. D. (1973). Progressive relaxation training: A manual for the helping professions. Champaign, IL: Research Press.
3. Bernstein, D. A., Borkovec, T. D., & Hazlett-Stevens, H. (2000). New directions in progressive relaxation training: A guidebook for helping professionals. Westport, CT: Praeger Publishers.
4. Boone, D. R. (1977). The voice and voice therapy. Englewood Cliffs, NJ: Prentice-Hall.
5. Crits-Christoph, P., Luborsky, L., Kron, R., & Fishman, H. (1978). Blood pressure, heart rate and respiratory responses to a single session of relaxation: A partial replication. Journal of Psychosomatic Research, 22, 493–501.