APA (7th ed.) Citation

Geological Survey (U.S.). (1974). Index map of Minnesota showing availabilty of flood-prone area maps (April 1974.). Geological Survey.

Chicago Style (17th ed.) Citation

Geological Survey (U.S.). Index Map of Minnesota Showing Availabilty of Flood-prone Area Maps. April 1974. St. Paul, Mn: Geological Survey, 1974.

MLA (9th ed.) Citation

Geological Survey (U.S.). Index Map of Minnesota Showing Availabilty of Flood-prone Area Maps. April 1974. Geological Survey, 1974.