1. Proc;BARTLETT, M.s;Camb. phil. Soc,1938
2. CHISHOLM, I. A., BRONTE-STEWART, j., and FOULDS, W. S. (1967) Lancet, 2, 450
3. Amer;CUNHA-VAZ, J.G.; MAURICE, D.M.;J. Physiol; Scand,1967
4. Canad;KIDD, H.M.; GOULD, C.E.G.; THOMAS, j w;med. Ass. J,1963
5. PHILLIPS, C. I., AINLEY, R. G., VAN PEBORGH, P., WATSON-WILLIAMS, E. J., and BOTTOMLEY, A. C. (1968)