Knieling, J. ., Fürst, D. . and Danielzyk, R. . (2001) “Can the value of regional planning be enhanced by the use of co-operation-based approaches?”, Raumforschung und Raumordnung | Spatial Research and Planning. DE, 59(2-3), pp. 184–191. doi: 10.1007/BF03184353.