5Hilde D. Fine-tuning Sugar Beet Fertility Management in the Red River Valley. Better Crop with Plant Food.1994,78(4):26~28
6Wright N A. New Mobile Sampler Compared to Hand Probes and Augers for Fertility Evaluation. Precision Agriculture ,1996. 631~639
7Algerbo, Sweden P A. Variable Nitrogen Application:Effects on Crop Yield and Quality. Proceeding of the Fourth International Conference on Precision Agriculture.1999. 709~717
8Leclerc H Laurent. F Dannis Biosgotier. France . Using Field and Crop Characteristics for Site Specific Nitrogen Management on Winter Wheat Crop. Proceeding of the Fourth International Conference on Precision Agriculture.1999. 719~731
9Ancha Srinivasan. Precision Farming in Asia: Progress and prospects. Proceeding of the Fourth International Conference on Precision Agriculture. 1999. 623~636
10VanBergeik, Goense J. D Soil Tillage Resistance as Tool to Map Soil Type Differences. Precision Agriculture.1996. 605~613