1. Bertinchamps, A.J., S.T. Miller, and G.L. Cotzias, ‘Interdependence of routes excreting manganese’, Am. J. Physiol. 211 (1966) 217.
2. Bremner, I. in C.F. Mills (ed.), Trace Element Metabolism in Animals, (Edinburgh, Livingstone, 1970), p. 366.
3. Büttner, W. and J.C. Muhler, ‘Effect of dietary iron on phosphate metabolism’, Proc. Soc. Exper. Biol. Med. 100 (1959) 440.
4. Cotzias, G.C., ‘Importance of trace substances in environmental health as exemplified by manganese’, in D.D. Hemphill (ed.), Trace Substances in Environmental Health-I, (Columbia, University of Missouri, 1967) p. 5.
5. Dreosti, I.E., ‘Cytochrome oxidase activity in copper deficient adult rats,’ S. African J. Agric. Sci. 10 (1967) 95.