1. Luppens, J. A., Scott, D. C., Osmonson, L. M., Haacke, J. E. & Pierce, P. E. Assessment of Coal Geology, Resources, and Reserve Base in the Powder River Basin, Wyoming and Montana (2013).
2. EIA U.S. Energy Information Administration Monthly Energy Review. Available at: https://www.eia.gov/totalenergy/data/monthly/ (2016).
3. Ayers, W. B. Jr Coalbed gas systems, resources, and production and a review of contrasting cases from the San Juan and Powder River basins. AAPG Bull. 86, 1853–1890 (2002).
4. Jones, N. R., Quillinan, S. A. & McClurg, J. E. Wyoming Coal (Wyoming State Geological Survey, 2009).
5. Swindell, G. S. Powder River Basin coalbed methane wells-reserves and rates. Rocky Mountain Oil & Gas Technology Symposium (Society of Petroleum Engineers, 2007).