Mittheilungen aus dem telegraphen-ingenieurbüreau des reichs-postamts
Cavi telegrafici sottomarini : costruzione, immersione, riparazione / Emanuele Jona
Exploatarea Telefoanelor / Constantin Chiru
List of oceanic depths and serial temperature observationd : received at the admiralty during the year 1895, from H.M surveying ships, indian marine survey and british submarine telegraph companie / Hydrographic Department