@article{Singer2008,
author = {Singer, E. and Couper, M.P.},
title= {Do incentives exert undue influence on survey participation? Experimental evidence},
year = {2008},
doi = {10.1525/jer.2008.3.3.49},
journal = {Journal of Empirical Research on Human Research Ethics},
volume = {3},
number = {3},
pages = {49--56},
}