1. CANSIM: Births 2005. Statistics Canada. September 21, 2007; catalogue no. 84F0210XIE.
2. Estimated pregnancy rates by outcome for the United States, 1990–2004;Ventura;Natl Vital Stat Rep,2008
3. Age at menarche and racial comparisons in US girls;Chumlea;Pediatrics,2003
4. Trends in twin and triplet births: 1980–97;Martin;Natl Vital Stat Rep,1999
5. Emergency Department Services in Ontario: Atlas Report (1993–2000);Chan,2001