Schonlau, Matthias, Martin Reuter, Juergen Schupp, Christian Montag, Bernd Weber, Thomas Dohmen, Nico A. Siegel, Uwe Sunde, Gert G. Wagner, and Armin Falk. 2010. “Collecting Genetic Samples in Population Wide (Panel) Surveys: Feasibility, Nonresponse and Selectivity”. Survey Research Methods 4 (2), 121-26. https://doi.org/10.18148/srm/2010.v4i2.3959.