Djajakirana, Gunawan. “Direct and Indirect Methods of Soil Microbial-Biomass Determination: Weakness and Strength”. Jurnal Ilmu Tanah dan Lingkungan 5, no. 1 (April 1, 2003): 29-38. Accessed August 25, 2024. https://jai.ipb.ac.id/index.php/jtanah/article/view/2331.