[Postcard from John Patterson Osterhout to Paul Osterhout, May 21, 1886], postcard, May 21, 1886; (https://texashistory.unt.edu/ark:/67531/metapth255510/m1/2/: accessed July 16, 2024), University of North Texas Libraries, The Portal to Texas History, texashistory.unt.edu; .