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Are there financing constraints for R & D and investment in German manufacturing firms?
Harhoff, Dietmar, (1996)
R&D spillovers, technological proximity, and productivity growth - evidence from German panel data
Harhoff, Dietmar, (2000)
Methodik und Einsatz hedonischer Preisindizes : ein Überblick
Harhoff, Dietmar, (1995)