1. European Laboratory Guidelines for Legally Defensible Workplace Drug Testing, Version 1.0, 2002, www.ewdts.org/guidelines (June 2, 2007).
2. Mandatory Guidelines for Federal Workplace Drug Testing Programs, SAMHSA September 1, 1994, www.workplace.samhsa.gov/ResourceCenter (June 2, 2007).
3. World Anti-Doping Code—2007 Code Amendments, June 1, 2007, World Anti-Doping Agency Code Version 2.0, www.wada-ama.org (June 2, 2007).
4. ISO/IEC 17025:2005 Incorporating Corrigendum no. 1, Published under the authority of the Standards Policy and Strategy Committee on June 29, 2005, ISBN 0 580 46330 3.
5. Statement of the Society of Hair Testing concerning the examination of drugs in human hair;Society of Hair Testing;Forensic Sci. Int.,1997