@book{ 0-832869333, title = {Patent productivity of German professors over the life cycle}, series = {Working papers in innovation and space}, author = {Proff, Sidonia von}, address = {Marburg}, publisher = {Philipps University Marburg, Department of Geography}, year = {2009}, language = {English}, url = {http://hdl.handle.net/10419/111863}, url = {https://katalog.hgb-leipzig.de/Record/0-832869333} }