The economics of new educational media :    vol.3 : cost and effecti veness overview and synthesis /  
Jean-Claude Eicher ...[et al] 
 - Paris :    The Unesco Press,    1982 
 - 150 p. :    ill. ;    24 cm. 
<br/><br/>Includes bibliographical references (p.143 - 150) 
<br/><br/><label>Subjects--Topical Terms: </label><br/> Teaching -- Aids and devices