De Bono, Edward,  1933-. <br/><br/>
PO, beyond yes & no / 
Edward de Bono. 
 - Rev. ed. 
 - Hammondsworth :  Penguin Books Ltd,  1973. 
 - 176 pages :  illustrations ;  18 cm. 
<br/><br/><label>ISBN: </label>0140217150 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Creative thinking.<br/>Thought and thinking.