1. Anderson, W. A. D., and Dmytryk, E. T. (1946). Amer. J. Path., 22, 337.
2. Bahnson, H. T., and Newman, E. V. (1953). Bull. Johns Hopk. Hosp., 93, 150.
3. Guy's Hosp;Brewin, T.B.;Rep,1951
4. Edwards, A. T., and Johnson, W. (1959). Brit. J. Surg., 46, 371.
5. Goldberg, H. P., and Steinberg, I. (1955). Circulation, 11, 963.