共 90 条
[63]
Measuring the social return to R&D
[J].
QUARTERLY JOURNAL OF ECONOMICS,
1998, 113 (04)
:1119-1135
[64]
Does intellectual property protection spur technological change?
[J].
OXFORD ECONOMIC PAPERS-NEW SERIES,
2003, 55 (02)
:235-264
[69]
LEVIN RC, 1987, BROOKINGS PAP ECO AC, P783