s20.
Elinor Ostrom, “A General Framework for Analyzing Sustainability of Social-Ecological Systems”, Science, 325, 5939, 2009, pp 419–22. See also summary in IU News Room, “Social Scientist Suggests New Research Framework to Study Complex Systems”, 23 July 2009, available at http://newsinfo.iu.edu/news/page/normal/11424.html .