Mohapatra, M, D Hariprasad, and S Anand. 2013. “SULPHURIC ACID LEACHING OF LOW MEDIUM GRADE Mn ORES USING A NOVEL NITROGENEOUS REDUCTANT- NH3NH2HSO4”. Journal of Mining and Metallurgy, Section B: Metallurgy 49 (1): 97. https://asistent.ceon.rs/index.php/jmm/article/view/2357.