The Grolier Children's Encyclopedia  5 Hippopotamus- Lungs 

 - Kingfisher Books Plc. ,London  Kingfisher Book Plc.  1998 
 - 239 
<br/><br/><label>ISBN: </label>0753403110 
<br/><br/><label>Dewey Class. No.: </label>RO30J98g 1998 V.5