United States. General Accounting Office. Railroad Regulation: Changes in Freight Railroad Rates from 1997 through 2000, report, June 7, 2002; (https://digital.library.unt.edu/ark:/67531/metadc295134/m1/1/: accessed April 19, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .