"Vom Straßenrand auf den Acker" [From the side of the road to the field] (in German). 19 February 2009. Archived from the original on 19 April 2017. Retrieved 21 April 2017.
"Vom Straßenrand auf den Acker" [From the side of the road to the field] (in German). 19 February 2009. Archived from the original on 19 April 2017. Retrieved 21 April 2017.