Identifying and gaining access to hidden populations.
Wiebel
W W
WW
Epidemiology-Biometry Program, School of Public Health, University of Illinois, Chicago 60612.
D003151:Community Health Centers / Q000458:organization & administration; D005007:Ethnology / Q000379:methods*; D006801:Humans; D011369:Professional-Patient Relations; D012106:Research / Q000191:economics / Q000458:organization & administration; D012107:Research Design; D019966:Substance-Related Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology