Reconnoissance soil survey of South Texas
Coffey, George Nelson and United States. Bureau of Soils.. Reconnoissance soil survey of South Texas, Book, June 16, 1910; digital images, (http://texashistory.unt.edu/ark:/67531/metapth19753 : accessed March 20, 2010), University of North Texas Libraries, The Portal to Texas History, http://texashistory.unt.edu; crediting UNT Libraries, Denton, Texas.