Johnson, Carl August Sr. 1893 - 1977. Correspondence, 1963 – 1971. SMHC Manuscript Collection 1380, Southern Minnesota Historical Center, Memorial Library, Minnesota State University, Mankato.

Johnson, Carl August Sr. 1893 - 1977. Correspondence, 1963 – 1971. SMHC Manuscript Collection 1380, Southern Minnesota Historical Center, Memorial Library, Minnesota State University, Mankato. https://archivesspace.lib.mnsu.edu/public/repositories/4/resources/402 Accessed April 29, 2024.