BALLARD, Philip Boswood <br/><br/>
Teaching the essentials of arithmetic / 
[by] Philip Boswood Ballard 
 - London  University of london press  1928 
 - xxi, 260 p. 
<br/><br/> Includes index 
<br/><br/><label>ISBN: </label>72310 
<br/><br/><label>Dewey Class. No.: </label>371.3511  / BAL