Amarov, Boyko, and Ulrich Rendtel. “The Recruitment of the Access Panel of German Official Statistics from a Large Survey in 2006: Empirical Results and Methodological Aspects”. Survey Research Methods 7, no. 2 (June 30, 2013): 103–114. Accessed April 24, 2024. https://ojs.ub.uni-konstanz.de/srm/article/view/5069.