1. Maternal mortality in the past and its relevance to developing countries today;Loudon;Am J Clin Nutr,2000
2. Death in childbirth: an international study of maternal care and maternal mortality 1800-1950;Loudon,1992
3. The history of obstetrics and gynaecology;O'Dowd,2004
4. Maternal mortality: who, where, when and why;Ronsmans;Lancet,2006
5. Secular trends in maternal mortality in Sweden from 1750 to 1980;Hogberg;Bull World Health Organ,1986