Smith, Sydney F. <br/><br/>
Telegphony and Telegraphy A :  an introduction to intruments and exchnage (step-by-step and common control) 
Sydney F. Smith 
 - 2nd ed. 
 - London :  Oxford University press,  1974 
<br/><br/><label>ISBN: </label>0198593465 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Telegraphy<br/>Telephony
<br/><br/><label>Dewey Class. No.: </label>621.385  / SMI