@article{Dillman2007,
author = {Dillman, D.A. and Smyth, J.D.},
title= {Design effects in the transition to web-based surveys},
year = {2007},
doi = {10.1016/j.amepre.2007.03.008},
volume = {32},
number = {5},
pages = {90--96},
}