N. GHOSH, S. GANGULY, & A. K. BANIK. (2011). Comparison Of Microbial Humic Acid Produced By Aspergillus Niger X1 And Soil Humic Acid. International Journal of Pharma and Bio Sciences, 2(2`), 479–484. Retrieved from https://ijpbs.net/index.php/journal/article/view/853