Moreira, M.A. 1991. Direct expansion method for estimating soybean and corn area through multitemporal and espectral LANDSAT/TM1 data. Pesquisa Agropecuaria Brasileira. 26, 10 (Oct. 1991), 1607–1613. DOI:https://doi.org/10.1590/S1678-3921.pab1991.v26.3503.