1. Prediction of the trafficability on soft paddy field (I). Tractor sinkage and the cone index;Tanaka;JSAM, J (Journal of the Society of Agricultural Machinery, Japan),1964
2. Prediction of the trafficability on soft paddy field (II). Cone index and soil hardness by YAMANAKA's meter;Tanaka;JSAM, J.,1964
3. Prediction of the trafficability on soft paddy field (III). Measurement device of the soil parameters, TN-4;Tanaka;JSAM, J.,1965
4. Prediction of the trafficability on soft paddy field (IV). On the drawbar pull of the tractors and their running elements;Tanaka;JSAM, J.,1966
5. Prediction of the trafficability on soft paddy field (V). Drawbar pull of the tractors and their sinkage;Tamaka;JSAM, J.,1966