Haranath, D., Savvi Mishra, Amish G. Joshi, Sonal Sahai, and Virendra Shanker. 2011. “Effective Doping of Rare-Earth Ions in Silica Gel: A Novel Approach to Design Active Electronic Devices”. Nano-Micro Letters 3 (3):141-45. https://doi.org/10.1007/BF03353664.