HoyertDL, The changing profile of autopsied deaths in the United States, 1972–2007. NCHS Data Brief, No. 67. Hyattsville (MD): National Center for Health Statistics (US); August 2011.
2.
CohenRAAdamsPF, Use of the Internet for health information: United States, 2009. NCHS Data Brief, No. 66. Hyattsville (MD): National Center for Health Statistics (US); July 2011.
3.
ParkMCherryDDeckerSL, Nurse practitioners, certified nurse midwives, and physician assistants in physician offices. NCHS Data Brief, No. 69. Hyattsville (MD): National Center for Health Statistics; August 2011.