1. Bell, R.N. (1950). Inorganic syntheses, Vol. III, L.F. Audrieth, ed., p. 103. New York: McGraw Hill
2. Griffith, E.J., Buxton, R.L. (1967). J.Am.Chem.Soc. 89, 2884
3. Handschuh, G.J., Lohrmann, R., Orgel, L.E. (1973). J.Mol.Evol. 2, 251
4. Kenyon, D.H., Steinman, G. (1969). Biochemical predestination. New York: McGraw-Hill
5. Knollmueller, K.O., U.S.Patent 3,333,921 (1967). Chem.Abstr. 67, 74990C