MacKenzie, Norman,  1921-2013 <br/><br/>
Études ouvertes :  Systems d´instruction postsecondaire á distance/ 
Norman Mackenzie, Richmond Postgate, John Scupham. 
 - Paris :  UNESCO,  1977. 
 - 448 p. 
<br/><br/><label>ISBN: </label>9232013266 9231013262 (softbound) 9231013327 (hardbound) 
<br/><br/><label>No. de Clasificación Universal Decimal: </label>374 (100) =40 MAC