Fardous, M. R., M. S. Nasrin, M. E. Shakil, M. S. Islam, M. A. Hoque, and M. N. Islam. “Cow Urine for Enhancement of Biogas Production and Fertilizer Quality of Biogas Slurry”. Journal of Scientific Research, vol. 12, no. 1, Jan. 2020, pp. 135-44, doi:10.3329/jsr.v12i1.43031.