TY - BOOK AU - Young,H.L. TI - Hydrogeology of the Cambrian-Ordovician aquifer system in the northern midwest, United States T2 - U.S. Geological Survey professional paper AV - GB1017 .Y67 1992 U1 - 551.49/0977 20 PY - 1992/// CY - Washington PB - U.S. G.P.O. KW - Water, Under ground KW - Middle West KW - Local KW - Geology, Stratigraphic KW - Ordovician KW - Cambrian KW - Aquifers N1 - Includes bibliographical references ER -