1. United States Department of Health and Human Services, Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS);National Vital Statistics System,2012
2. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC);Vital Signs: Prescription Painkiller Overdoses in the US;National Center for Injury Prevention and Control, Division of Unintentional Injury Prevention, last updated: November 1, 2011,2011