How to keep open-source based innovation approaches sustainable : a view from the intellectual property perspectiveHoffmann, Thomas; Prause, Gunnar KlausJournal of entrepreneurship and sustainability issues2015 / p. 133-141 http://dx.doi.org/10.9770/jesi.2014.2.3(2) Intellectual property rights in user-driven innovation processesHoffmann, Thomas; Prause, Gunnar Klaus13th International Entrepreneurship Forum (13th IEF) Conference "Entrepreneurship and Development : The Idea of Inclusive Opportunity Creation" : 31 July - 2 August, 2014, Bogota, Colombia : conference proceedings2014 / p. 366-384