共 50 条
- [2] INDUSTRIALIZATION OF UNITED-STATES AGRICULTURE, AN INTERPRETIVE ATLAS - GREGOR,HF [J]. PROFESSIONAL GEOGRAPHER, 1983, 35 (04): : 502 - 503
- [4] GEOGRAPHY OF AGRICULTURE - GREGOR,HF [J]. MITTEILUNGEN DER OSTERREICHISCHEN GEOGRAPHISCHEN GESELLSCHAFT, 1973, 115 (1-3): : 292 - 292
- [6] FUTURE OF UNITED-STATES BEEKEEPING AND UNITED-STATES AGRICULTURE [J]. AMERICAN BEE JOURNAL, 1986, 126 (04): : 273 - 275