Ardley, Neil; Ridpath, Lan & Harben, Peter <br/><br/>
The universe and the earth 

 - Macdonald educational ltd., London  1978 
 - 133 
<br/><br/><label>ISBN: </label>0 356 05761 5 
<br/><br/><label>Dewey Class. No.: </label>523 Ard