Powell, Leonard Sutherland <br/><br/>
A guide to the overhead projector 
by Len Powell 
 - 2nd ed. 
 - London  British Association for Commercial and Industrial Education  1970 
 - 32 p. : ill. ; 22 cm. 
<br/><br/><label>ISBN: </label>0851710107 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Lantern projection<br/>Transparencies