1. Bailey, N. T. J. (1951). J. Hyg., Lond., 49,81.
2. New Types of Old Americans at Harvard and at Eastern Women's Colleges.;Bowles, G.T.;Brit. med. J,1932
3. Cathcart, E. P., Hughes, D. E. R., and Chalmers, J. G. (1935). Rep. Industr. Hlth Res. Board, Lond., No. 71.
4. Durnin, J. V. G. A., and Weir, J. B. de V. (1952). Brit. med. J., 1, 1006.
5. Friend, G. E., and Bransby, E. R. (1947). Lancet, 2, 677.