Casler, Howard M. The Oklahoma Labor Unit (Oklahoma City, Okla.), Vol. 2, No. 48, Ed. 1 Saturday, May 13, 1911, newspaper, May 13, 1911; (https://gateway.okhistory.org/ark:/67531/metadc106985/m1/1/: accessed April 22, 2018), University of North Texas Libraries, The Gateway to Oklahoma History, gateway.okhistory.org; .