1. History of the Mineral Industry in Nigeria with Notes on the Geological Survey of Nigeria, Federal Ministry of Mines and Power, Lagos, Nigeria, 1987.
2. Wah Chang of New York, U.S. Patent 3,193,376, 1965.
3. H.N. Sinha, D.M. Waugh, A process for the beneficiation of titaniferous ores, Britain Patent No. 1,255,826, 1971.
4. Benelite of America, U.S. Patent 3,825,419, 1974.
5. M. Robinson, F. Clamp, D. Aberdeen, D.B. Mobbs, R.V. Pearce. Beneficiation of ilmenite ores, U.S. Patent 3,875,286, 1975.