Structural and Optical Studies of Ho\(^{3+}\) Yb\(^{3+}\) Co-Doped TiO\(^{2}\) Nanoparticles in Silica Glass. Jour. Atomic Mole. Conden. Nano Phys 2016, 3 (2), 61-71. https://doi.org/10.26713/jamcnp.v3i2.462.