1. The status of the embryo from a Christian point of view;Folscheid;Ethics Med,1994
2. When does human life begin;Kurjak;Encyclopaedia Moderna,1992
3. Identity and status of the human embryo: the contribution of biology;Serra,1998
4. Developmental biology;Gilbert,1991
5. Personhood: a biological phenomenon;Scarpelli;J Perinat Med,2001