1. The Manganese Ores of the Lafayette District, Minas Geraes, Brazil;Singewald;Bull. A.I.M.E.,1916
2. Manganese Ores of Russia, India, Brazil, and Chile;Harder;Bull. A.I.M.E.,1916
3. The Manganese Ore Industry of the Caucasus;Drake;Trans A.I.M.E.,1898
4. Fermor, L. L., “The Manganese Ore Deposits of India,” “Memoirs Geological Survey of India,” vol. xxvvii, pts. 1–4
5. Harder, E. C., loc. cit.