CRITICAL MINERALS IN THE FOX HILLS (CRETACEOUS), HELL CREEK (CRETACEOUS) AND LUDLOW (PALEOCENE) FORMATIONS IN NORTH DAKOTA.Published in:Report of Investigation - North Dakota Geological Survey, 2022, v. 130, p. iBy:Moxness, Levi D.;Murphy, Edward C.;Kruger, Ned W.Publication type:Article