@article{Couper2013,
author = {Couper, M.P. and Kreuter, F. },
title= {Using paradata to explore item level response times in surveys},
year = {2013},
doi = {10.1111/j.1467-985X.2012.01041.x},
journal = {Journal of the Royal Statistical Society: Series A},
volume = {176},
pages = {271−286},
}