Donald A. Keefer,, Illinois State Geological Survey. (1995). Potential of Agricultural Chemical Contamination of Aquifers, 2004: Illinois. University of Illinois Urbana-Champaign, Illinois State Geological Survey. https://clearinghouse.isgs.illinois.edu/data/hydrology/potential-agricultural-chemical-contamination-aquifers

Available from: https://geo.btaa.org/catalog/5cde1dd4-f2f8-46a1-9054-f7d868d58a56