Synthesis of Mn-Doped ZnO Nanoparticles and Their Application in the Transesterification of Castor Oil oleh Afifa Zahid, Zahid Mukhtar, Muhammad Azam Qamar, Sammia Shahid, Syed Kashif Ali, Mohammad Shariq, Hussain J. Alathlawi, Mohd Abul Hasan, Mohd Shakir Khan, Saiful Islam, Bhagyashree R. Patil, Mohammed Saleh Al Ansari, Zahid Nawaz, Mudassar Sher