Geology of the forty-ninth parallel sheet no. 13, map 86 A.
Geology of the forty-ninth parallel sheet no. 13, map 86 A., map, .; [Ottawa, Ontario, Canada]. (texashistory.unt.edu/ark:/67531/metapth187407/: accessed February 22, 2018), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; crediting University of Texas at Arlington Library.