Lehnert, Josef. <br/><br/>
Introduction to telegraph engineering 

 - 2nd ed. 
 - Berlín-London :   Siemens-Heyden,   1977. 
 - 155 p. 
<br/><br/><label>ISBN: </label>0855012331 
<br/><br/><label>Subjects--Topical Terms: </label><br/>TELECOMUNICACIONES<br/>TELEGRAFIA<br/>TRASMISION DE DATOS
<br/><br/><label>Universal Decimal Class. No.: </label>621.394