Wittich, Walter Arno,  1910- <br/><br/>
Audiovisual materials :  their nature and use / 
by Walter Arno Wittich 
 - 4th ed. 
 - New York :  Harper & Row,  1967 
 - 554 p.:  ill.;  27 cm. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Audio-visual education