Azmi Yahya, M. Zohadie, A. F. Kheiralla, S. K. Gew. Tractor-implement performance mapping system. Standards and Industrial Research Institute of Malaysia, SIRIM. PI200414135.
Azmi Yahya, M. Zohadie, A. F. Kheiralla, S. K. Gew. A three-point auto hitch dynamometer. Standards and Industrial Research Institute of Malaysia, SIRIM. PI20040975.