Não informado. (2020). Records. Geological Survey Department.
Chicago-Zitierstil (17. Ausg.)Não informado. Records. Georgetown: Geological Survey Department, 2020.
MLA-Zitierstil (8. Ausg.)Não informado. Records. Geological Survey Department, 2020.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.