References
- ARNOLD , A. C. and THORNHILL , E. W. 1978 . An aural aid to govern walking speed . British Crop Protection Monograph , 22 : 149 – 150 .
- MATTHEWS , G. A. Suitability of pesticide application equipment take over for small scale farmers in tropical countries . Proceedings of 10th International Congress of Plant Protection . November 10–25 1983 , Brighton, England. Vol. 2 , pp. 517