1. Goldman, R. L., and Friedman, N. B. (1967). Cancer (Philad.), 20, 134.
2. Helwig, E. B., and Ranier, A. (1953). Surg. Gynec. Obstet., 96, 355.
3. Stout, A. P. (1949). Cancer (Philad.), 2, 1027.
4. EVANS (Cardiff) When a membrane such as a nuclepore filter (GEC) is applied to the ectocervix, cells from the cervical surface adhere to it; microscopical examination of the stained membrane provides a method foi assessing the topography of a carcinoma in situ of the ectocervix;D, D.M.,1967
5. Evans, D. M. D. (1967). Lancet, 2, 972.