Ralphs, J. D. <br/><br/>
Principles and practice of multi-frequency telegraphy / 
J. D. Ralphs. 
 - London, UK :  P. Peregrinus on behalf of the Institution of Electrical Engineers,  1985. 
 - x, 205 p. :  ill. ;  24 cm. 
 - IEE telecommunications series ;  11 .
<br/><br/> 'Errata' slip inserted. 
<br/><br/>Includes bibliographical references and index. 
<br/><br/><label>ISBN: </label>0863410227  RM332.20 
<br/><br/><label>LCCN: </label>84-224784 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Telegraph, Wireless.