Salt, Laura E, Ed.; Sinclair, Robert, Ed. <br/><br/>
Oxford junior encyclopedia, Vol.4: Communications 

 -  Oxford University Press  1957 
 - 496 
<br/><br/><label>Subjects--Topical Terms: </label><br/>General encyclopedic works
<br/><br/><label>Dewey Class. No.: </label>R 030  SAL-O.4