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 Duda, A. M. A1 Johnson, R. J. YR 1985 UL http://www.jswconline.org/content/40/1/108.abstract AB