1. F.F. Colcord “Treating Lead Bullion,” US Patent No. 1,386,503 (1921)
2. G.P. Hulst “Purifying Antimonial Lead Alloys,” US Patent No. 1523,980 (1925)
3. T.R.A. Davey “The Physical Chemistry of Lead Refining,” Lead-Zinc-Tin ′80, J.M. Cigan, T.S. Mackey and T.J. O'Keefe, Eds., The Metallurgical Society of AIME, Warrendale, PA., U.S.A., 1980, 477-507
4. Approximate Thermodynamic Data from the Systems Copper-bismuth, Copper-lead and Copper-thallium;Kleppa;J. Am. Chem. Soc.,1952
5. G.M. Willis private communication, 1948