Zwolle Quadrangle, map, 1941; (https://texashistory.unt.edu/ark:/67531/metapth457811/m1/1/: accessed July 9, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .
Zwolle Quadrangle, map, 1941; (https://texashistory.unt.edu/ark:/67531/metapth457811/m1/1/: accessed July 9, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu.; .