Findlay, A. (Alexander), 1790-1870. The world, with the tracts & discoveries of the latest navigators., map, [1820..1840]; (https://texashistory.unt.edu/ark:/67531/metapth192405/m1/1/: accessed July 17, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .