1. http://www.painmed.org/productpub/statements/pdfs/definition.pdf .
2. Diagnostic and Statistical Manual of Mental Disorders. Fourth Edition. Text Revision (DSM-IV-TR). American Psychiatric Association, 2000.
3. https://dawninfo.samhsa.gov/data/tables-08/national/Nation_2008_NMUP.xls#’ED Visits by Drug’!A1 (accessed March 24, 2010).
4. Parran VP, Wilford BB, DuPont RL: Prescription drug abuse. http://www.uptodate.com (accessed March 5, 2010).
5. Kuehn BM. Prescription drug abuse rises globally. J Am Med Assoc. 2007;297:1306.