3) DENG Zhourong and YOUG Shucheng: Interaction Between Soil and Driving Wheels for Paddy Field Tractor, Tractor, No. 6, pp. 7-16, Luoyang Institute of Tractor, 1986
4) ASAE Standard: ASAE S296.2 “UNIFORM TERMINOLOGY FOR TRACTION OF AGRICULTURAL TRACTORS, SELF-PROPELLED IMPLEMENTS, AND OTHER TRACTION AND TRANSPORT DEVICES”, ASAE STANDARD 1986, pp. 197-199, 1986