Unwin, Derick <br/><br/>
The encyclopaedia of educational media communications and technology / 
Derik Unwin and Ray McAleese 
 - London :  The Macmillan press,  1978 
 - 800 p. :  ill. ;  24 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Audio-visual materials--Dictionaries