Wallace, Robert L.; Taylor, Water K. & Litton, James R. <br/><br/>
Back and Braithwaite's  Invertebrate zoology 

 - 4th ed 
 - Macmillan Publishing company, New York  1989 
 - pp. xii, 337 
<br/><br/><label>ISBN: </label>0-02-307763-8 
<br/><br/><label>Dewey Class. No.: </label>592.072 Wal