The Alumina Content of the Bear Den Member (Golden Valley Formation) and the Rhame Bed (Slope Formation) in Western North Dakota by Murphy, E. C., 2013. Available on CD for $5.00.
Alumina Content of the Bear Den Member & the Rhame Bed in ND. Murphy, Edward, 2012. Available in traditional paper map format ($10.00), or on CD with pdf ($5) or with shape files for ($25.00). Shape files require GIS or other mapping related software to open.