 Map of valley of Red River in Texas, Oklahoma, and Arkansas between meridian 96°30′ and 98° west longitude: From topographic maps of the U.S. Geological Survey,&amp;nbsp;map,&amp;nbsp;1920;&amp;nbsp;Austin, Texas. ( texashistory.unt.edu/ark:/67531/metapth492933/ :&amp;nbsp;accessed May 28, 2017),&amp;nbsp;University of North Texas Libraries, The Portal to Texas History,&amp;nbsp; texashistory.unt.edu ; crediting Hardin-Simmons University Library. 