1. Ruthruff, R. F.Desulphurizing hydrocarbon oils. U.S. Patent 1,938,672 A, Dec 12, 1933.
2. Bearden, R., Jr. and Hamner, G. P.Combined catalytic and alkali metal hydrodesulfurization and conversion process. U.S. Patent 3,976,559 A, Aug 24, 1976.
3. Baird, W. C., Jr. and Bearden, R., Jr.Combined desulfurization and hydroconversion with alkali metal hydroxides. U.S. Patent 4,003,823 A, Jan 18, 1977.
4. Baird, W. C., Jr., Bearden, R., Jr., and Ledford, T. H.Hydroconversion with group IA, IIA metal compounds. U.S. Patent 4,127,470 A, Nov 28, 1978.
5. Brons, G., Myers, R. D., and Bearden, R., Jr.Continuous in-situ combination process for upgrading of heavy oil. U.S. Patent 5,935,421 A, Aug 10, 1999.