Simulation of regional ground-water flow in the Cambrian-Ordovician aquifer system in the northern Midwest, United States / by R.J. Mandle and A.L. Kontis.
Imprint
[Reston, Va.?] : U.S. Dept. of the Interior, U.S. Geological Survey ; Denver, CO : For sale by Book and Open-File Report Sales, 1992.