Kohler, Martin. 2015. „Das einsame Auge und weite Landschaften. Von Cowboys und Kollaborateuren.“ S. 7–11 in Pixelprojekt Ruhrgebiet. Neuaufnahmen 2014/2013. Gelsenkirchen.
http://www.pixelprojekt-ruhrgebiet.de
https://www.researchgate.net/
http://www.pixelprojekt-ruhrgebiet.de
https://www.researchgate.net/
„The usefulness of walking-based research is more evident when the object of analysis is a large urban area. In these cases, maps and satellite images rely on highly aggregated data and only allow for the identification of visual patterns from a large distance. As an alternative, Chapter 8 proposes „big urban walks“ crossing whole metropolitan areas. This method produces information that while subjective, it is also coherent and systematic, and can be used to understand the complex social and physical factors behind the patterns observed in maps.“