Hayyan, A., Alam, M. Z., Mirghani, M. E. S., Kabbashi, N. A., Mohd Siran , Y., & Mohd. Hakimi , N. I. N. (2009). Production of biodiesel from sludge palm oil by esterification using P-toluenesulfonic acid.

Hayyan, Adeeb, Md. Zahangir Alam, Mohamed Elwathig Saeed Mirghani, Nassereldeen Ahmed Kabbashi, Yosri Mohd Siran , and Noor Irma Nazashida Mohd. Hakimi. Production of Biodiesel From Sludge Palm Oil By Esterification using P-toluenesulfonic Acid. 2009.

Hayyan, Adeeb, et al. Production of Biodiesel From Sludge Palm Oil By Esterification using P-toluenesulfonic Acid. 2009.