Key points are not available for this paper at this time.
Richard C. Levin, Alvin K. Klevorick, Richard R. Nelson, Sidney G. Winter, Richard Gilbert, Zvi Griliches, Appropriating the Returns from Industrial Research and Development, Brookings Papers on Economic Activity, Vol. 1987, No. 3, Special Issue On Microeconomics (1987), pp. 783-831
Levin et al. (Thu,) studied this question.