1. The Influence of Certain Inorganic Salts on the Flotation of Lead Carbonate;Ray;Transactions of the American Institute of Mining Engineers,1950
2. Principals of flotation;Wark;Melbourne Institute of Mining and Metallurgy,1938
3. Flotation of oxide lead zinc and copper ore;Ray;Institute of Mining and Metallurgy,1954
4. Effect of Alkalinity on the Flotation of Lead Minerals;Fleming;Transactions of the American Institute of Mining Engineers,1952
5. Usoni, L., Rinelli, G., and Marabini, A.M., Chelating Agents and Fuel Oil: A New Way to Flotation, AIME General Annual Meeting. New York, USA;1971.