1. Mineral Facts and Problems, Bureau of Mines, 1980 edition.
2. Review of major proposed processes for recovering manganese from United States resources;Henn;Bureau of Mines IC 8368,1968
3. Processing manganiferrous sea nodules;Brooks;Bureau of Mines RI 7473,1971
4. Selective extraction of metals from Pacific Sea Nodules with dissolved sulfur dioxide;Khalafalla;Bureau of Mines R.I. 8518,1981
5. Extraction behavior of metal elements from deep-sea manganese nodules in reducing media;Han;Marine Mining,1980