Piper, Charles V. (Charles Vancouver), 1867-1926 & Morse, W. J. (William Joseph), b. 1884. The Velvetbean., book, May 1938; (https://digital.library.unt.edu/ark:/67531/metadc5937/m1/1/: accessed July 15, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .