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1by 131618 Williams, L.S., 130457 Walter, B.J., 94911 Moldenhauer, W.C., 79004 Hudson, N.W. eds., 18125 Soil and Water Conservation Society, Ankeny, Iowa (EUA), 21136 World Association of Soil and Water Conservation, 39136 Workshop Conservation Farming on Steep Lands San Juan (Puerto Rico) 22-27 Mar 1987
Published 1988bibliotecaIICA