Alexander, E. C., Jr., Falteisek, Jan, Witthuhn, Kathleen, M. (1996). Geologic atlas of Fillmore County, Minnesota, C-8, Part B, Plate 8, Sinkholes and Sinkhole Probability. Minnesota Department of Natural Resources, Division of Waters. https://reflections.mndigital.org/catalog/mgs:730 (map)