Sung Lim, Chang. “Cyclic Microwave-Assisted Sol-Gel Process of KGd(MoO4)2:Er3+ Yb3+ Phosphors and Upconversion of Their Photoluminescence Properties”. Asian Journal of Chemistry, vol. 27, no. 7, Mar. 2015, pp. 2598-02, doi:10.14233/ajchem.2015.18428.