United States. Bureau of the Census. 1990 Census County Block Map (Recreated): Zapata County, Inset B07, map, 1990; (https://texashistory.unt.edu/ark:/67531/metapth362938/m1/1/: accessed July 9, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .