International Hydrological decade. 

 - Paris :  UNESCO,  1968. 
 - various p. ;  26 cm.  
<br/><br/>61  61 
<br/><br/><label>Subjects--Topical Terms: </label><br/>International Hydrology.
<br/><br/><label>Dewey Class. No.: </label>551.4906 / U3f