Handayani, T. M., R. Nugroho, L. Hidayati, D. W. A. Fatmawati, and A. Sumono. “Effects of Glycerin Application on the Hardness of Nanofilled Composite Immersed in Tamarind Soft Drinks”. Dental Journal, vol. 52, no. 2, June 2019, pp. 95-99, doi:10.20473/j.djmkg.v52.i2.p95-99.