Khalil, A., and huda Jassim. “IMPROVING OF BIOGAS PRODUCTION USING DIFFERENT PRETREATMENT OF RICE HUSK INOCULATED WITH OSTRICH DUNG”. The Journal of Engineering Research [TJER], vol. 18, no. 1, Oct. 2021, pp. 1-11, doi:10.53540/tjer.vol18iss1pp1-11.