"The Sequoyah System" Tulsa Tribune; "Phonetic Alphabets" Washington Post, Box 1, Folder 5, Item 9
Owen, Robert L. (Robert Latham), 1856-1947. "The Sequoyah System" Tulsa Tribune; "Phonetic Alphabets" Washington Post, Box 1, Folder 5, Item 9, Robert L. Owen Collection, 1913-1946. Carl Albert Congressional Research and Studies Center. https://fraser.stlouisfed.org/archival/5300/item/535388, accessed on April 19, 2024.