19th Century engraving of a French Post Coach
Air mail (General information and Rates), 1931.
Air mail posting Timetable, Issue 12, 15th February 1961.
Air mails from United Kingdom to Australia.
Annual report 1959 - North Borneo.
Annual report of the postmaster general of the United States for the fiscal year ended June 30, 1881.
Archbold New Guinea Expedition 1938-9
Articles relating to Sunday deliveries
Ascension Island Postal History by Neil Macfall and Edward Proud "before going to print"
Berlin Post Office Headquarters
British & French Post Boxes (1835)
British N. Borneo, Post & Telegraph guide - 1925.