Wnuck, Corinna (30 August 2010). "Tui-Großaktionär stockt Anteil auf" [Tui major shareholder increases stake]. Finance (dalam bahasa Jerman). Diakses tanggal 22 October 2018.
Wnuck, Corinna (30 August 2010). "Tui-Großaktionär stockt Anteil auf" [Tui major shareholder increases stake]. Finance (dalam bahasa Jerman). Diakses tanggal 22 October 2018.