United States. Bureau of the Census. 1990 Census County Block Map (Recreated): Pecos County, Inset D20, map, 1990; (https://texashistory.unt.edu/ark:/67531/metapth363895/m1/1/: accessed May 21, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .