共 7 条
[1]
CARBAJO J, 1990, J IND ECON, V33, P283
[4]
David P. A., 1990, EC INNOVATION NEW TE, V1, P3, DOI DOI 10.1080/10438599000000002
[5]
FARRELL J, 1987, PRODUCTION STANDARDI
[7]
WHINSTON MD, 1990, AM ECON REV, V80, P837