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2. S. C. DAS, L. B. SUKLA, and P. K NAIK: ‘Report On extrac-tion of manganese from oxidic manganese ores - a review’, Report T/H&EM/302/Ju1y/1999, Regional Research Laboratory (CSIR), Bhubaneswar, Orissa, India, 1999.
3. Percolation leaching of manganese ore by aqueous sulfur dioxide
4. Leaching of a rich Greek manganese ore by aqueous solutions of sulphur dioxide