Koga, L. J., Canteri, M. G. and Godoy, C. V. (2007) “Relationships between measures of reflectance and health leaf area, soybean rust severity and soybean yield”, Semina: Ciências Agrárias, 28(4), pp. 571–580. doi: 10.5433/1679-0359.2007v28n4p571.