共 15 条
[7]
HALVORSON AD, 1982, USDAARS180 PROD RES
[8]
HALVORSON AD, 1985, MONT AG RES, V2, P19
[9]
Little T.M., 1978, AGR EXPT DESIGN ANAL
[10]
OLSEN SR, 1954, USDA939 CIRC