1. Angle, E. H. (1907).Malocclusion of the teeth. Angle's system. Philadelphia: S. S. White Dental Manufacturing Co.
2. Azrin, H. N., & Holz, H. C. (1966). Punishment. In W. K. Honig (Ed.),Operant behavior: Areas of research and application (pp. 380?447). New York: Appleton-Century-Crofts.
3. Baer, D. M. (1977). Perhaps it would be better not to know everything.Journal of Applied Behavior Analysis, 10 167?172.
4. Barlow, D. H., & Hersen, M. (1984).Single case experimental designs: Strategies for studying behavior. New York: Pergamon Press.
5. Beck, A. T. (1976).Cognitive therapy and the emotional disorders. New York: International Universities Press.