Jieqiong M, Hongguang Z, Min F. Distribution of heavy metals in pig farm biogas residues and the safety and feasibility assessment of biogas fertilizer. Int J Agric & Biol Eng [Internet]. 2013 Dec. 25 [cited 2026 Feb. 27];6(4):35-43. Available from: https://www.ijabe.migration.pkpps06.publicknowledgeproject.org/index.php/ijabe/article/view/1008