1. Contraception and abortion from the ancient world to the renaissance;Riddle,1992
2. Death in childbirth: an international study of maternal care and maternal mortality 1800–1950;Loudon,1992
3. Contraception in the Roman Empire;Hopkins;Comparative Studies in Society and History,1965
4. Hurst WJ & Hurst DJ. Hellebore. In: Medicina Antiqua, Wellcome Trust Centre for the History of Medicine at UCL. www.ucl.ac.uk.
5. Latin Christianity: its founder, Tertullian, Ch XXV;Schaff,1896