共 22 条
[2]
BABCOCK BA, 1993, J AGR RESOUR ECON, V18, P17
[4]
CHAMBERS R, 1989, AM J AGR ECON, V71, P606
[8]
HOLTHAUSEN DM, 1979, AM ECON REV, V69, P989
[10]
*IOW STAT U U EXT, 1996, EXT B FM, V1712