Dutch, Steven. "Portage Canal"Archived 2011-07-20 at the Wayback Machine, Natural and Applied Sciences, University of Wisconsin - Green Bay, retrieved February 22, 2011.
web.archive.org
Dutch, Steven. "Portage Canal"Archived 2011-07-20 at the Wayback Machine, Natural and Applied Sciences, University of Wisconsin - Green Bay, retrieved February 22, 2011.