1. N. D. Chasteen (ed.),Vanadium in Biological Systems; Kluwer, Dordrecht, 1990.
2. D. Rehder,Angew. Chem. internat. edit. 30, 148 (1991).
3. D. Rehder,Bio Metals 5, 3 (1992).
4. F. H. Nilsen and E. O. Uthus, in ref. 1, p. 51.
5. B. J. Stoecker and L. H. Hopkins inBiochemistry of the Essential Ultra-trace Elements (E. Frieden, ed.), Plenum, New York, 1984.