Unwin, Derick. <br/><br/>
The Encychlopaedia of Educational Media Communications and Technolgy. 
Unwin Derick 
 - Westport    Greenwood press 
<br/><br/><label>ISBN: </label>313201291 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Audio - Visual materials - Dictionaries.
<br/><br/><label>LC Class. No.: </label>REF LB 1042 5 U5 1978