United States. Bureau of the Census. 2000 Census County Subdivison Block Map: Clifton CCD, Texas, Block 4, map, 2000; (https://texashistory.unt.edu/ark:/67531/metapth418244/m1/1/: accessed March 19, 2019), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .