1. 74th Annual Session of the American Dental Association;Clark,1932
2. A Survey of Color Education in the Dental Schools of the World;Sproull;United States Army Research Report,1968
3. Color Matching in Dentistry. Part I. The Three-Dimensional Nature of Color;Sproull;J. Prosthet. Dent.,1973
4. Color Matching in Dentsitry. Part II. Practical Applications of the Organization of Color;Sproull;J. Prosthet. Dent.,1973
5. Principles of Color Technology;Billmeyer,1967