1. Spectrophotometric analysis of color differences between porcelain systems;Seghi;J Prosthet Dent,1986
2. Tooth color selection;Clark;J Am Dent Assoc,1933
3. Double layer effect and other optical phenomena related to esthetics;O'Brien;Dent Clin North Am,1985
4. Double-layer color effects in porcelain systems;O'Brien;J Dent Res,1985
5. Kubelka-Munk reflectance theory applied to porcelain veneer systems using a colorimeter;Davis;Int J Prosthodont,1994