Bracmort, Kelsi; Ramseur, Jonathan L.; McCarthy, James E.; Folger, Peter & Marples, Donald J. Methane Capture: Options for Greenhouse Gas Emission Reduction, report, January 7, 2011; (https://digital.library.unt.edu/ark:/67531/metadc821498/m1/1/: accessed October 17, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .