Bailey, Roy D. <br/><br/>
Improving concentration :  evaluating and improving concentration and performance / 
Roy D. Bailey and Elvie Brown 
 - London :  Speechmark ,  2015 
 - viii, 1544 pages :  colour illustrations ;  26 cm. 
<br/><br/>Includes bibliographical references 
<br/><br/><label>ISBN: </label>9780863889103 (cased) 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Concentration