Piva, Evandro, Lourenço Correr-Sobrinho, Mario Alexandre Coelho Sinhoreti, Simonides Consani, Flávio Fernando Demarco, and John Michael Powers. 2008. “ Influence of Energy Density of Different Light Sources on Knoop Hardness of a Dual-Cured Resin Cement ”. Journal of Applied Oral Science 16 (3): 189-93. https://doi.org/10.1590/S1678-77572008000300005.