Fraunhofer-Institut für Medienkommunikation IMK (26 March 2002). "Beethoven digitally". Beethoven-haus-bonn.de. Archived from the original on 12 April 2017. Retrieved 5 May 2009.
"MUSEUMSMEILE BONN". museumsmeilebonn.de (in German). Retrieved 3 February 2017.
"MUSEUMSMEILE BONN". museumsmeilebonn.de (in German). Retrieved 3 February 2017.
nationalatlas.de
aktuell.nationalatlas.de
Sebastian Lentz (17 June 2011). "Nationalatlas aktuell". Hauptstadtbeschluss. Archived from the original on 31 March 2013. Retrieved 20 September 2012.
Sebastian Lentz (17 June 2011). "Nationalatlas aktuell". Hauptstadtbeschluss. Archived from the original on 31 March 2013. Retrieved 20 September 2012.
Fraunhofer-Institut für Medienkommunikation IMK (26 March 2002). "Beethoven digitally". Beethoven-haus-bonn.de. Archived from the original on 12 April 2017. Retrieved 5 May 2009.