Hesse, Markus, and Annick Leick. “Growth, Innovation, Metropolitan Regions. Reconstructing the Recent Modernisation of Spatial Development Guidelines in Germany”. Raumforschung Und Raumordnung | Spatial Research and Planning, vol. 71, no. 4, Aug. 2013, pp. 343–359, https://doi.org/10.1007/s13147-013-0243-x.