Ackoff, Russell L.  1919-, <br/><br/>
On purposeful systems / 
by Russell L. Ackoff and Fred E. Emery. 
 - London :  Tavistock Publications,  1972. 
 - xii, 288 pages :  illustrations ;  25 cm. 
<br/><br/>Includes bibliographies. 
<br/><br/><label>ISBN: </label>0422740306 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Social sciences--Methodology.<br/>Social systems.