Ashraf, S., M. Hussain, M. W. Mumtaz, and M. Shuaib. “Biodiesel Production by Alkali Catalyzed Transesterification of Chicken and Beef Fats”. International Journal of Alternative Fuels and Energy, vol. 1, no. 1, Dec. 2017, pp. 14-20, https://psmjournals.org/index.php/ijafe/article/view/130.