ISBN 3-89853-562-2 (in German)==External links==* Francis Fox, How the Swiss Built the Greatest Tunnel in the World, 1905* German language site: AlpenTunnel.de: Simplon-Tunnel* description of the construction of the tunnel
ISBN 3-89853-562-2 (in German)* Francis Fox, How the Swiss Built the Greatest Tunnel in the World, 1905* Сайт на немецком языке: AlpenTunnel.de: Simplon-Tunnel