Clarkson E.N.K., <br/><br/>
Invertebrate plaeontology and evolution 
by E.N.K. Clarkson 
 - 4th ed. 
 - Delhi  Wiley India Pvt. Ltd.  2012 
 - xiv, 452p. 
<br/><br/><label>ISBN: </label>978-81-265-3308-4 
<br/><br/><label>Dewey Class. No.: </label>K1(H6)ObG:66  / Q2