The Oklahoma Labor Unit (Oklahoma City, Okla.), Vol. 1, No. 47, Ed. 1 Saturday, May 15, 1909, newspaper, May 15, 1909; (https://gateway.okhistory.org/ark:/67531/metadc107618/m1/1/: accessed May 16, 2024), University of North Texas Libraries, The Gateway to Oklahoma History, gateway.okhistory.org; .