The numbers about people affected by color deficient vision are based on:
Birch, J. 1993. Diagnosis of Defective Colour Vision. Oxford University Press, 204 pp.
Piantanida, T. 1991. Genetics of inherited colour vision deficiencies, in: Inherited and acquired colour vision deficiencies: Fundamental aspects and clinical studies, 88-114, ed. by Foster, D. H., Keele, UK.
Pickford, R. W. 1959. Some heterozygous manifestations of colour blindness. British Journal of Physiological Optics, 16:83-95.
Pokorny, J., Smith, V. C., Verriest, G. and Pinkers, A. J. L. G. (eds.) 1979. Congenital and acquired color vision defects. New York: Grune & Stratton.
