1. Colebrook (1930).Brit. Med. Jo., ii, 134.
2. Colebrook and Hare (1933).Jo. Obst. Gyn., 40, 609.
3. Harris and Brown (1929).Bull. Johns Hopkins Hosp., 44, No. 1.
4. Harris and Brown (1927).Bull. Johns Hopkins Hosp., 40, No. 4.
5. Brown, J. H. (1919).Monograph No. 9,Rockefeller Institute for Med. Res.