1. Nutrients in ground water and surface water of the United States--an analysis of data through 1992 Author/Creator: Mueller, David K., author Publication/Creation: Denver, Colorado : U.S. Geological Survey, 1995 Resource Type: Book Access & Availability: Loading
2. Nutrients in shallow ground waters beneath relatively undeveloped areas in the conterminous United States Author/Creator: Nolan, Bernard T., 1954- Publication/Creation: Denver, Colo. : U.S. Dept. of the Interior, U.S. Geological Survey, 2003 Resource Type: Book Access & Availability: Loading