Olson, Kristen, James M. Lepkowski, and David H. Garabrant. “An Experimental Examination of the Content of Persuasion Letters on Nonresponse Rates and Survey Estimates in a Nonresponse Follow-Up Study”. Survey Research Methods 5, no. 1 (April 30, 2011): 21–26. Accessed July 19, 2024. https://ojs.ub.uni-konstanz.de/srm/article/view/4324.