Nadler, Robert, Knut Petzold, and Robert Schönduwe Diplom-Geograph. 2015. “Doing Online Surveys in Socio-Scientific Regional Studies: Issues and Experiences”. Raumforschung Und Raumordnung | Spatial Research and Planning 73 (3): 203–217. https://doi.org/10.1007/s13147-015-0341-z.