2James P. Warner, Lucie wright, Martin Blanchard and Michael King.The psychological health and quality of life of older lesbians and gay men: a snowball sampling pilot survey INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY Int J Geriatr Psychiatry 2003, 18:754-755.
3[3]Cheng F. DC Des Darlais. HIV among drug users in China.Science, 2002, 298:1171.
4Heckathorn DD, Jeffri J. Finding the beat: Using respondent-driven sampling to study jazz musicians. Poetics, 2001,28 (4) : 307-329.
5Heckathorn DD. Respondent-Driven Sampling II: Deriving Valid Population Estimates from Chain-Referral Samples of Hidden Populations. Social Problems, 2002, 49(1) : 11-34.
6Wang JC, Carlson RG, Falck RS, et al, Respondent-driven sampling to recruit MDMA users: A methodological assessment. Drug and Alcohol Dependence, 2005, 78(2) : 147-157.
7Salganik MJ, Heckathorn DD. Sampling and estimation in hidden population using Respondent-Driven Sampling. Sociology Methodology, 2004, 34(1) :193-240.
8Heckathorn DD. Respondent-Driven Sampling: A new Approach to the Study of Hidden Populations. Social Problems, 1997, 44(2) : 174-199.