Sung Lim, Chang. “Spectroscopic Study and Green Upconversion of BaGd2(MoO4)4:Er3+ Yb3+ Phosphors via Cyclic Microwave-Modified Sol-Gel Route”. Asian Journal of Chemistry, vol. 27, no. 1, Dec. 2014, pp. 297-00, doi:10.14233/ajchem.2015.17406.