RT Journal Article SR Electronic T1 Cost-effective targeting of agricultural nonpoint-source pollution controls JF Journal of Soil and Water Conservation FD Soil and Water Conservation Society SP 108 OP 111 VO 40 IS 1 A1 A. M. Duda A1 R. J. Johnson YR 1985 UL http://www.jswconline.org/content/40/1/108.abstract AB