Philips Telecommunication Review. 

 - Hilversum :  N.V.Philips Telecommunicatie Industrie,  1968. 
 - v. :  gráficos.,fotos ;  29 cm. 
<br/><br/> El texto viene de la p.105 a la 148. 
<br/><br/>V.27 N.3 Reed switches for telephony switching. Amplitude-modulated voice-frequency telegraph system type 3TR 1100.