Hennings, George <br/><br/>
Keep Earth clean, blue & green :  environmental activities for young people / 
George Hennings, Dorothy Grant Hennings 
 - New York :  Citation Press,  1976 
 - vi, 250 p. :  ill. ;  21 cm. 
<br/><br/>Bibliography: p. 227-236. 
<br/><br/><label>ISBN: </label>0590074601 
<br/><br/><label>LCCN: </label>75-042336 //r81 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Environmental education<br/>Environmental protection--Study and teaching