Keyes, Nelson Beecher. <br/><br/>
The American frontier :  our unique heritage / 
Nelson Beecher Keyes. 
 - Garden City, N.Y. :  Hanover House,  1954. 
 - 384 p. ;  21 cm. 
<br/><br/>Includes index. 
<br/><br/><label>Subjects--Geographic Terms: </label><br/>United States--Territorial expansion.
<br/><br/><label>Dewey Class. No.: </label>973  / KEA 1954