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- [4] MARKET-STRUCTURE, FIRM STRUCTURE, AND RESEARCH-AND-DEVELOPMENT QUARTERLY REVIEW OF ECONOMICS AND BUSINESS, 1986, 26 (01): : 31 - 44
- [5] THE HERFINDAHL FIRM CONCENTRATION INDEX FOR AN ANALYSIS OF MARKET-STRUCTURE TRIMESTRE ECONOMICO, 1994, 61 (243): : 499 - 524
- [9] FIRM SIZE, MARKET-STRUCTURE, OPPORTUNITY, AND THE OUTPUT OF PATENTED INVENTIONS AMERICAN ECONOMIC REVIEW, 1965, 55 (05): : 1097 - 1125