Map of the Swiss telephone network
Overview map for the Swiss post bus guide, 1892 (PTT archive)
Map of the Swiss telephone network, 1889 (PTT archive)
Map of the Swiss telephone network, 1893 (PTT archive)
The Swiss Post Office Guide to the Alps, 1930 (PTT archive)
Local call B, 1992 (PTT archive)
Zwitserland Alpenpostdiensten, 1946 (PTT archive)