Häfner, Karl. “Cluster Organizations in Praxis: Structural and Institutional Influences on a Cluster-Orientated Promotion of Economic Development”. Raumforschung Und Raumordnung | Spatial Research and Planning, vol. 74, no. 5, Oct. 2016, pp. 421–436, https://doi.org/10.1007/s13147-016-0422-7.