Networks of action situations : a systematic review of empirical research - Kimmich, Christian (Masaryk University. Department of Environmental Studies) ; Baldwin, Elizabeth (University of Arizona. School of Government and Public Policy) ; Kellner, Elke (Swiss Federal Institute for Forest. Snow and Landscape Research) ; Oberlack, Christoph (University of Bern. Institute of Geography) ; Villamayor Tomás, Sergio (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)