@article{Groves2000,
author = {Groves, R.M. and Singer, E. and Corning, A. },
title= {Leverage-saliency theory of survey participation: Description and an illustration},
year = {2000},
doi = {10.1086/317990},
journal = {Public Opinion Quarterly },
volume = {64},
number = {3},
pages = {299−308},
}