Vannieuwenhuyze, Jorre T.A., and Melanie Revilla. “Relative Mode Effects on Data Quality in Mixed-Mode Surveys by an Instrumental Variable”. Survey Research Methods 7, no. 3 (November 22, 2013): 157–168. Accessed October 14, 2024. https://ojs.ub.uni-konstanz.de/srm/article/view/5137.