Permian Basin (North America) – Wikipedia
Bakken Formation Oil & Gas | Map, News, Lease, Royalty Info
North Dakota Petroleum Council
Department of Mineral Resources, North Dakota
North Dakota Department of Environmental Quality
North Dakota Industrial Commission
Bureau of Land Management North Dakota
California Independent Petroleum Association
Western States Petroleum Association
U.S. Energy Information Administration – California
California Department of Conservation – Oil, Gas, and Geothermal (DOGGR)