Dipl.-Ing. Benjamin Wiechmann, Dipl.-Ing. Claudia Dienemann, Dr. Christian Kabbe, M. Sc. Simone Brandt, Dr. Ines Vogel,Dr. Andrea Roskosch. "Sewage sludge management in Germany"(PDF). www.umweltbundesamt.de. Umweltbundesamt(UBA). Retrieved October 20, 2017.{{cite web}}: CS1 maint: multiple names: authors list (link)
