How valuable is patent protection?
Subtitle: estimates by technology field using patent renewal data
By: Mark Schankerman.
Contributors: National Bureau of Economic Research.
Series: NBER working papers series -- working paper no. 3780; Working paper series (National Bureau of Economic Research) -- working paper no. 3780.
Publisher: National Bureau of Economic Research
Published: 1991
Place of publication: Cambridge, MA
Language: eng
Number of pages: 38
Subjects: Patents -- Valuation -- Econometric models.; Patents -- France -- Econometric models.
Notes: "July 1991."

Includes bibliographical references.

Binghamton University Libraries' copy bound with: An analysis of the nature of unemployment in Sri Lanka.