1. Relation between selected well-construction characteristics and occurrence of bacteria in private household-supply wells, south-central and southeastern Pennsylvania Author/Creator: Zimmerman, Tammy M. Publication/Creation: New Cumberland, Pa. : U.S. Dept. of the Interior, U.S. Geological Survey, 2001 Resource Type: Book Access & Availability: Loading
2. Relations of biological indicators to nutrient data for lakes and streams in Pennsylvania and West Virginia, 1990-98 Author/Creator: Brightbill, Robin A. Publication/Creation: New Cumberland, Pa. : U.S. Dept. of the Interior, U.S. Geological Survey, 2003 Resource Type: Book Access & Availability: Loading