@article{Curtin2005,
author = {Curtin, R. and Presser, S. and Singer, E.},
title= {Changes in telephone survey nonresponse over the past quarter century},
year = {2005},
doi = {10.1093/poq/nfi002},
journal = {Public Opinion Quarterly },
volume = {69},
number = {1},
pages = {87−98},
}