1. Field performance of tractor draught control systems;Cowell;J. agric. Engng Res.,1967
2. A survey of control requirements and unscheduled stops during tillage operations, part II: ploughs, cultivators and rotary cultivators 1971–1972;Dwyer;N.I.A.E. Department note DN/CT/272/1261,1972
3. An electro-hydraulic servo for investigating methods of controlling the working depth of a tractor-mounted implement;Harries;N.I.A.E. Departmental note DN/CT/084/1410,1971
4. A three-point linkage dynamometer for restrained linkages;Scholtz;J. agric. Engng Res.,1966
5. Automatic control of tractor mounted implements;Cowell,1969