Jan Wandel; Christina Wisotzky; Florian Pantillon; Bernhard Mühr; Florian Becker; Daniel Friederich; Jonas Straub; Susanna Mohr (31 January 2018). "Wintersturm Friederike"(PDF). www.cedim.de (in German). Archived(PDF) from the original on 18 February 2022. Retrieved 20 July 2023.
Jan Wandel; Christina Wisotzky; Florian Pantillon; Bernhard Mühr; Florian Becker; Daniel Friederich; Jonas Straub; Susanna Mohr (31 January 2018). "Wintersturm Friederike"(PDF). www.cedim.de (in German). Archived(PDF) from the original on 18 February 2022. Retrieved 20 July 2023.