1. Australian Bureau of Criminal Intelligence (ABCI), 2002. Australian Illicit Drug Report 2000/01. Commonwealth of Australia, Canberra.
2. Australian Crime Commission (ACC), 2003. Australian Illicit Drug Report 2001/02. Commonwealth of Australia, Canberra.
3. Australian Institute of Health and Welfare (AIHW), 2000. Statistics on drug use in Australia 1998. AIHW Cat. No. PHE 16. AIHW (Drug Statistics Series), Canberra.
4. Snowball sampling: problems, techniques and chain referral sampling;Biernacki;Sociol. Methods Res.,1981
5. Levels and correlates of polydrug use among heroin users and regular amphetamine users;Darke;Drug Alcohol Depend.,1995