Tuning the Optical Properties of ZnO by Co and Gd Doping for Water Pollutant Elimination oleh Kashif Safeen, Akif Safeen, Danish Arif, Wiqar H. Shah, Akhtar Ali, Ghafar Ali, Fayaz Hussain, Naveed Imran, Atta Ullah Shah, Abed Alataway, Ahmed Z. Dewidar, Hosam O. Elansary, Mohamed Al-Yafrsi, Khawaja Shafique Ahmad