Tables give data on developments for 1923-1929; number of letters and parcels carried.
Survey of air-mail traffic according to lines
Aufsatz (Zeitschrift)
Royal mail lines' M.S. "Drina."
Engineering Index Backfile | 1945
Engineering Index Backfile | 1929
|Monitoring of employee e-mail traffic
IEEE | 2004
|13.0307 Monitoring of Employee E-mail Traffic
British Library Conference Proceedings | 2004
|"Loch Garth" for Royal mail lines cargo service
Engineering Index Backfile | 1947