Jürgens, Tim; Hitzlsperger, Thomas (30 April 2020). ""Genießen konnte ich Spiele nie"" ["I never enjoyed playing"] (in German). 11 Freunde. Retrieved 28 January 2021.
"Der "Held von Auxerre" prüft die Kasse" [The "Hero of Auxerre" checks the cash register] (in German). Borussia Dortmund. 4 December 2013. Retrieved 24 October 2019.