Não informado. (2001). Bulletin of the Wisconsin Geological and Natural History Survey. Wisconsin Geological and Natural History Survey.
Chicago-Zitierstil (17. Ausg.)Não informado. Bulletin of the Wisconsin Geological and Natural History Survey. Madison, Wis: Wisconsin Geological and Natural History Survey, 2001.
MLA-Zitierstil (8. Ausg.)Não informado. Bulletin of the Wisconsin Geological and Natural History Survey. Wisconsin Geological and Natural History Survey, 2001.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.