Manuals of telegraph and telephone engineering

＜図書＞
Manuals of telegraph and telephone engineering


1	Telephonic transmission : theoretical and applied / by J.G. Hill London : Longmans, Green , 1920
2	Printing telegraph systems and mechanisms / by H. H. Harrison London : Longmans, Green , 1923
3	The inspection and testing of materials, apparatus and lines / by F.L. Henley London : Longmans, Green , 1923