Salt, Laura E.. <br/><br/>
Oxford Junior Encyclopaedia Vol-4 /  

 - Reprinted 1976 /  
 - London W.1 :   Oxford University Press. 
 - p.496,xvi :  
<br/><br/><label>Subjects--Topical Terms: </label><br/>Communications
<br/><br/><label>Dewey Class. No.: </label>K56,N4  / H8,L6.4