hat
Al., Rosemarie (September 11, 2007). « Advance Data From Vital and Health Statistics, Drug Use and Sexual Behaviors Reported by Adults in the United States, 1999 – 2002 » (PDF).
eng
Al., Rosemarie (September 11, 2007). "Advance Data From Vital and Health Statistics, Drug Use and Sexual Behaviors Reported by Adults in the United States, 1999 – 2002" (PDF).