Bluemke, Matthias, Bernd Resch, Clemens Lechner, René Westerholt, and Jan-Philipp Kolb. “Integrating Geographic Information into Survey Research: Current Applications, Challenges and Future Avenues”. Survey Research Methods 11, no. 3 (October 20, 2017): 307-327. Accessed March 1, 2021. https://ojs.ub.uni-konstanz.de/srm/article/view/6733.