1. D-norgestrel in postcoital administration. Preliminary report;Larrañaga,1971
2. Compounds interfering with ovum implantation and development;Morris;Am. J. Obstet. Gynec.,1966
3. Oral contraception after the coitus;Morris,1968
4. Postcoital fertility regulation. The influence of high doses of estrogens on implantation;Haspels,1971
5. Estrógenos en grandes dosis después del coito;Haspels;Bol. Méd. IPPF.,1972