Young, H. L. <br/><br/>
Summary of ground-water hydrology of the Cambrian-Ordovician aquifer system in the northern Midwest, United States / 
by H.L. Young 
 - Washington :  U.S. G.P.O.,  1992 
 - vi, 55 p. :  ill. (some col.), col. maps ;  29 cm. 
 - Regional aquifer-system analysis--northern Midwest .
 - U.S. Geological Survey professional paper ;  1405-A .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Groundwater--Middle West<br/>Aquifers--Middle West<br/>Geology, Stratigraphic--Cambrian<br/>Geology, Stratigraphic--Ordovician
<br/><br/><label>Dewey Class. No.: </label>551.490977