@article{Toepoel2008,
author = {Toepoel, V. and Das, M. and Van Soest, A.},
title= {Effects of design in web surveys: Comparing trained and fresh respondents},
year = {2008},
doi = {10.1093/poq/nfn060},
volume = {72},
number = {5},
pages = {985--1007},
}