United States. Bureau of the Census. P.L. 94-171 County Block Map (2010 Census): Madison County, Index, map, January 7, 2011; (https://texashistory.unt.edu/ark:/67531/metapth387612/m1/1/: accessed May 21, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .