MARSHALL, A.J. WILLIAMS, W.D. <br/><br/>
TEXTBOOK OF ZOOLOGY, Volume I: INVERTEBRATES . 

 - 7th Ed. 
 - London  Macmillan and Company Limited, London   1982 
<br/><br/><label>ISBN: </label>0 333 14107 5 
<br/><br/><label>Dewey Class. No.: </label>592  / MAR/T