Construction and maintenance of lines (War Office) - Engeland Voorschrift, 26/Manuals/381 Signal Training. Pamphlet no. 8. Signal Office Organization and Procedure. Part I. Procedure for Morse Telegraphy, Line Telephony and Visual Signalling.1944 - Engeland Voorschrift Line unit BE-77-A and line unit BE-77 - USA Voorschrift, Technical Manual, 11-359
