1. Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research;Caspersen;Public Health Rep,1985
2. Canadian guidelines for exercise in pregnancy;Wolfe;Clin Obstet Gynecol,2003
3. Number 267, January 2002: exercise during pregnancy and the postpartum period;ACOG Committee opinion;Obstet Gynecol,2002
4. The effect of exercise on the intensity of low back pain in pregnant women;Garshasbi;Int J Gynaecol Obstet,2005