MacKenzie, Norman,  1921-2013 <br/><br/>
Open Learning : Systems and problems in post-secondary education/ Norman Mackenzie, Richmond Postgate, John Scupham. 

 - Paris : UNESCO, 1975 
 - 498 p. .
<br/><br/><label>ISBN: </label>9231013262 
<br/><br/><label>No. de Clasificación Universal Decimal: </label>374 (100) MAC