Matsuo, Hideko, Jaak Billiet, Geert Loosveldt, Frode Berglund, and Øyven Kleven. 2010. “Measurement and Adjustment of Non-Response Bias Based on Non-Response Surveys: The Case of Belgium and Norway in the European Social Survey Round 3”. Survey Research Methods 4 (3):165-78. https://doi.org/10.18148/srm/2010.v4i3.3774.