@article{Singer1999,
author = {Singer, E. and Van Hoewyk, J. and Gebler, N. and Raghunathan, T. and McGonagle, K.},
title= {The effect of incentives on response rates in interviewer-mediated surveys},
year = {1999},
journal = {Journal of Official Statistics},
volume = {15},
number = {2},
pages = {217--230},
}