Text this: Elastic, structural and optical studies on ᵪNa₂O-(35-ᵪ)V₂O₅-65TeO₂,ƴWO₃-(40-y)Ag₂O-60TeO₂ AND zNb₂O₅-(20-z)BaO-80TeO₂ tellurite based glass systems / Muhammad Umair Mohamad