1. Miller L. Organizing colour in dentistry. J Am Dent Assoc (Special Issue);26E–40E, 1987.
2. Clarke FJ. Measurement of color of human teeth. In: McLean JW, editor. Dental ceramics, Proceedings of the First International Symposium on Dental Ceramics. Chicago, IL: Quintessence, 1983.
3. Preston J. The elements of esthetics—Application of color science. In: McLean JW, editor. Dental Ceramics, Proceedings of the First International Symposium on Dental Ceramics. Chicago, IL: Quintessence, 1983.
4. Spectrophotometric study of five porcelain shades relative to the dimensions of color, porcelain thickness and repeated firings;Jorgenson;J Prosthet Dent,1979
5. An analysis of tooth color;Clark;J Am Dent Assoc,1931