Improvement in Combining Bitumen and Clay., patent, September 24, 1872; (https://texashistory.unt.edu/ark:/67531/metapth166801/m1/1/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .
Improvement in Combining Bitumen and Clay., patent, September 24, 1872; (https://texashistory.unt.edu/ark:/67531/metapth166801/m1/1/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .