1. Births: final data for 2004: national vital statistics reports;Martin,2006
2. Contribution of assisted reproductive technology and ovulation-induction drugs to triplet and higher-order multiple births: United States, 1980-1997;MMWR Morb Mortal Wkly Rep,2000
3. Increasing trends in plural births in the United States;Jewell;Obstet Gynecol,1995
4. Trends in multiple births conceived using assisted reproductive technology, United States, 1997-2000;Reynolds;Pediatrics,2003
5. Assisted reproductive technologies: estimates of their contribution to multiple births and newborn hospital days in the United States;Wilcox;Fertil Steril,1996