Shrock, Robert R. and Twenhofel, William H. <br/><br/>
Principles of Invertebrate Paleontology 

 - New York  McGrew-Hill Book Company, Inc.  1953 
 - 816 
<br/><br/><label>Subjects--Personal Names: </label> Zoology 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Zoology