Eaux rares =  Precious waters = Aguas preciadas / 
Unesco. 
 - Paris :  Unesco,  1981. 
 - various pagination;  col. ill.: 
<br/><br/><label>ISBN: </label>9230019631 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Water<br/>Water quality