National and regional estimates of the prevalence of opiate use and/or crack cocaine use 2005/06: a summary of key findings / RDS, 20 November 2007
PDF - http://www.homeoffice.gov.uk/rds/pdfs07/rdsolr2107.pdf
Gordon Hay ; Maria Gannon ; Jane MacDougall ; Tim Millar ; Catherine Eastwood ; Neil McKeganey
Home Office Online Report 21/07