APA
Hall B. H., National Bureau of Economic Research, Helmers C. & Graevenitz G. V. (2015). Technology entry in the presence of patent thickets. Cambridge: NBER.
Chicago
Hall Bronwyn H, National Bureau of Economic Research, Helmers Christian and Graevenitz Georg Von. 2015. Technology entry in the presence of patent thickets. Cambridge: NBER.
Harvard
Hall B. H., National Bureau of Economic Research, Helmers C. and Graevenitz G. V. (2015). Technology entry in the presence of patent thickets. Cambridge: NBER.
MLA
Hall Bronwyn H, National Bureau of Economic Research, Helmers Christian and Graevenitz Georg Von. Technology entry in the presence of patent thickets. Cambridge: NBER. 2015.