1. National Research Council, “Precision agriculture in the 21st century,” p. 149, National academy Press, Washington D.C., 1997.
2. N. Noguchi, K. Ishii, and H. Terao, “Development of an agricultural mobile robot using a geomagnetic direction sensor and image sensors,” J. of Agricultural Engineering Research, Vol.67, No.1, pp. 1-15, 1997.
3. I. S. Ahmad, J. F. Reid, N. Noguchi, and A. C. Hansen, “Nitrogen sensing for precision agriculture using chlorophyll maps,” ASAE Paper 993035, 1999.
4. L. F. Tian, J. F. Reid, and J. F. Hummel, “Development of a precision sprayer for site specific weed management,” Trans. of the ASAE, Vol.42, No.4, pp. 893-900, 1999.
5. N. Kondo, M. Monta, and N. Noguchi, “Agricultural robots – mechanisms and practice –,” Kyoto University Press, 2011.