@article{Magnani2005,
author = {Magnani, R. and Sabin, K. and Saidel, T. and Heckathorn, D.D. },
title= {Review of sampling hard-to-reach and hidden populations for HIV surveillance},
year = {2005},
doi = {10.1097/01.aids.0000172879.20628.e1},
journal = {AIDS},
volume = {19},
number = {Suppl. 2},
pages = {S67--S72},
}