TY - BOOK AU - Siegel,Donald I. ED - United States TI - Geochemistry of the Cambrian-Ordovician aquifer system in the Northern Midwest, United States U1 - 553.790977 19th ed. PY - 1989///. CY - Washington: PB - United States Government Printing Office, KW - Water KW - Composition KW - Middle West KW - Geochemistry KW - Aquifers KW - Geology, Stratigraphic KW - Cambrian KW - Ordovician KW - Geology N1 - Includes bibliographical references (p. D56-D60) ER -