model answers to city and guilds of london institute examinations in elementary telecommunications practice : comprising answers to questions in elementary telecommunications practice in the years 1947 to 1955 / Post office electrical engineers' journal
model answers to city and guilds of london institute examinations in telecommunications principles II : including answers to similar questions in technical electricity, transmission and lines, and radio communication / Post office electrical engineers' journal
Circuits de transmission pour communications téléphoniques procédés d'étude et de détermination / K. S. Johnson; E. M. Deloraine, M. L. Drouët
verreschrijvers de telegraaf in huis over uw telefoonlijn