Potentiometric surface of the Ozark aquifer in northern Arkansas, 2004 [electronic resource] / by T.P. Schrader ; prepared in cooperation with the Arkansas Natural Resources Commission, and the Arkansas Geological Commission.
Imprint
Reston, Va. : U.S. Dept. of the Interior, U.S. Geological Survey, 2005.
Mode of access: Internet at the USGS web site. Address as of 8/22/08: http://pubs.usgs.gov/sir/2005/5208/SIR2005-5208.pdf ; current access is available via PURL.