1. R&D and the Patent Premium
2. Patent Renewals as Options: Improving the mechanism for weeding out lousy patents;Marc Baudry;Review of Industrial Organization,2006
3. A Study of Patent Mortality Rates: Using Statistical Survival Analysis to Rate and Value Patent Assets;Jonathan A Barney;AIPLA Quarterly Journal,2002
4. The Value of U.S. Patents by Owner and Patent Characteristics;James Bessen;Research Policy,2008