• 

  Statistik Schweiz - Infrastruktur

  http://wayback.archive.org/web/20130109123330/http://www.bfs.admin.ch/bfs/portal/de/index/themen/11/03/blank/key/infrastruktur.h

• 

  Statistik Schweiz - Infrastruktur

  https://web.archive.org/web/20101114002529/http://www.bfs.admin.ch/bfs/portal/de/index/themen/11/03/blank/key/infrastruktur.html

---

---