Wahlmann, G. P. <br/><br/>
Middle and Upper Ordovician symmetrical univalved mollusks (Monoplacophora and Bellerophontina) of the Cincinnati arch region 
G.P. Wahlmann. 
 - Washington  U.S. G.P.O.  1992. 
 - vi, 213, [90] p.  ill.  29 cm. 
 - Geological Survey professional paper  1066-0 .
<br/><br/>Includes bibliographical references. 
<br/><br/><label>LCCN: </label>89600358  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Monoplacophora, Fossil--Middle West.<br/>Paleontology--Middle west.<br/>Paleontology--Ordovician.<br/>Archaeogastropoda, Fossil--Middle West.
<br/><br/><label>LC Class. No.: </label>QE805  / .W35 1990 
<br/><br/><label>Dewey Class. No.: </label>564 
<br/><br/><label>Gov. Doc. Class. No.: </label>I 19.16:1066-0