1. Betts, Anson G., Lead Refining by Electrolysis. John Wiley and Sons (1908).
2. Mathers, F. C. and Lantz, G. B., United States Smelting. Refining and Mining Co., U.S. Patent 2.664.393. December 29, 1953.
3. Piontelli, R., Z. Electrochem.. Vol. 59, (1955), p. 778.
4. The Merck Index. Seventh Edition. Merck and Co. Inc. (1960), Page 39.
5. Hay, J. Evelyn and Haynes, L.J.,. J. Chem. Soc. 3141 (1965).