Gaddum, Leonard W. <br/><br/>
Our Physical Environment /  Leonard W. Gaddum and Harold L. Knowles 

 - Cambridge :  Houghton Mifflin Company,  1953. 
 - ix, 625 p. :  ill. ;  22cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Physical Environment 
<br/><br/><label>Dewey Class. No.: </label>551.4  / GAO 1953