Hussain, S., Malik, A. A., Shahzad, K., Akhthar, N. A., Ali, N., & Chughtai, A. (2015). Factors Influencing the Formation of Producer gas from Coal and Biomass; A Review. Journal of the Pakistan Institute of Chemical Engineers, 43(2), 133–147. Retrieved from http://piche.org.pk/journal/index.php/jpiche/article/view/197