NCHS Dataline

Early release of selected estimates based on data from the 2002 National Health Interview Survey. Hyattsville (MD): National Center for Health Statistics; 2003.

Hamilton B Martin J Ventura S Sutton P . Births: preliminary data for 2002. Natl Vital Stat Rep 2002;51(11).

McCaig L Burt C . National Hospital Ambulatory Medical Care Survey, 2001 emergency department summary, Adv Data 2003 Jun 4 (335); 1–29.