Statistik Schweiz - Kantone, Gemeinden

https://web.archive.org/web/20081215033605/http://www.bfs.admin.ch/bfs/portal/de/index/themen/01/02/blank/key/raeumliche_verteilung/kantone__gemeinden.html

Stuttgart Airport - Page 1 | Military Airfield Directory

http://www.mil-airfields.de/de/stuttgart-echterdingen.htm

The first aviation use of the area near Echterdingen was the unplanned landing of the airship LZ4 in 1908. In the 1930s the Echterdingen airport was built to replace the existing one at Böblingen.