1. Schenkl, S., Behncke, F., Hepperle, C., Langer, S., Lindemann, U. Managing cycles of innovation processes of product-service systems. In: 2013 IEEE International Conference on Systems, Man and Cybernetics. 2013, p. 918-923.
2. Langer, S., Knoblinger, C., Lindemann, U. Analysis of dynamic changes and iterations in the development process of an electrically powered go- kart. In: Marjanovic, D., Åtorga, M., Pavkovic, N., Bojcetic, N., editors. 11th International Design Conference DESIGN 2010. 2010, p. 307-318.
3. Baines, T., Lightfoot, H., Evans, S., Neely, A., Greenough, R., Pep- pard, J., et al. State-of-the-art in product-service systems. Proceedings of the Institution of Mechanical Engineers, Part B: journal of engineering manufacture 2007;221(10):1543-1552.
4. Schumpeter, J.A. Business cycles: A Theoretical, Historical and Statisti- cal Analysis of Capitalist Process. Cambridge University Press; 1939.
5. Andersen, B. The hunt for s-shaped growth paths in technological inno- vation: a patent study. Journal of Evolutionary Economics 1999;9(4):487-526.