Sources and transport of phosphorus and nitrogen during low-flow conditions in the Tualatin River, Oregon, 1991-93 [microform] / by Valerie J. Kelly, Dennis D. Lynch, and Stewart A. Rounds ; prepared in cooperation with the Unified Sewerage Agency of Washington County, Oregon (U.S. Geological Survey open-file report ; 99-232)
Sources and transport of phosphorus and nitrogen during low-flow conditions in the Tualatin River, Oregon, 1991-93 [microform] / by Valerie J. Kelly, Dennis D. Lynch, and Stewart A. Rounds ; prepared in cooperation with the Unified Sewerage Agency of Washington County, Oregon