Assessment of undiscovered oil resources in the Bakken and Three Forks Formations, Williston Basin Province, Montana, North Dakota, and South Dakota, 2013 - Gaswirth, Stephanie B.; Marra, Kristen; Cook, Troy; Charpentier, Ronald R.; Gautier, Donald; Higley, Debra; Klett, Timothy R.; Lewan, Michael D.; Lillis, Paul; Schenk, Christopher; Tennyson, Marilyn E.; Whidden, Katherine (Fact Sheet, 2013)