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2. The development and application of electro-hydraulic control system for Case 4WD tractors;Dobrinska;SAE paper No. 810941,1981
3. Tractor three-point hitch control system;Thomas;SAE paper No. 891835,1989
4. Utilization of ultrasonic wave sensor in plow depth control;Satow;Hokaido Br. of JSAM,1985
5. Microcomputer control system for tractor implements;Jiang;JSAM,1992