MacDonaldA. E. (1965). Causes of blindness in Canada. An analysis of 24,605 cases registered with the Canadian National Institute for the Blind. Canad. med. Ass. J., 92, 264.
2.
MillerH. (1967). In sickness and in health. Encounter, 28, 4, 10.
3.
SorsbyA. (1950). Medical Research Council Memorandum No. 24. London: H.M. Stationery Office.
4.
SorsbyA. (1966) Reports on Public Health and Medical Subjects No. 114. London: H.M. Stationery Office.