"Hennings, George" <br/><br/>
Keep earth clean blue and green : enviornmental activities for young people 

 - New York  Citation Press  1976 
 - 250 p. 
<br/><br/><label>ISBN: </label>590074601 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Pollution study and teaching
<br/><br/><label>Dewey Class. No.: </label>363.6 Hen