Frank, Susanne. “Urban Development through the EU: European Urban Policy and URBAN-Approach in the Area of Conflict of the Lisbon Strategy and the Leipzig Charter”. Raumforschung Und Raumordnung | Spatial Research and Planning, vol. 66, no. 2, Mar. 2008, pp. 107–117, https://doi.org/10.1007/BF03183121.