Soil map, Illinois, Knox County sheet., map, 1903; (https://texashistory.unt.edu/ark:/67531/metapth193398/m1/1/: accessed April 23, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .
Soil map, Illinois, Knox County sheet., map, 1903; (https://texashistory.unt.edu/ark:/67531/metapth193398/m1/1/: accessed April 23, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .