共 49 条
- [2] [Anonymous], 2001, Econometric Analysis of Cross-Section and Panel Data
- [3] [Anonymous], 2009, 20095019 US GEOL SUR
- [8] Delano D., 1997, An economic analysis of flood and center pivot irrigation system modifications
- [9] Dong D., 2001, AAEA ANN M CHIC 5 8