Gerlach, Vernon S. ,  1922- <br/><br/>
Teaching and media :  a systematic approach / 
Vernon S. Gerlach, Donald P. Ely. 
 - Englewood Cliffs, N.J. :  Prentice-Hall ,  1971. 
 - 392 p. :  ill. ;  24 cm. 
<br/><br/>Includes bibliographical references. 
<br/><br/><label>ISBN: </label>0138913331 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Audio--Visual education.<br/>Teaching--Aids and devices.