Waseem Mumtaz, Muhammad, Ahmed Adnan, Hamid Mukhtar, Farooq Anwar, Zahoor Ahmad, and Fahim Ashraf Qureshi. 2011. “Response Surface Methodology Based Process Optimization for Biodiesel Production Using Cottonseed Oil: A Comparative Study”. Asian Journal of Chemistry 24 (3):1075-81. https://asianpubs.org/index.php/ajchem/article/view/8714.