Horn, Sam. <br/><br/>
Improve your Concentration! / 
Sam Horn. 
 - London :  Kogan Page,  c1991. 
 - 102 p. 
<br/><br/><label>ISBN: </label>0749405848 
<br/><br/><label>LCCN: </label>93024122     
<br/><br/><label>Subjects--Topical Terms: </label><br/>Success--Psychological aspects.<br/>Mental discipline.<br/>Attention.