Wilker, Roger L., 1938-. Oral History Interview, 25 and 30 October 1989. SMHC Manuscript Collection 1406, Southern Minnesota Historical Center, Memorial Library, Minnesota State University, Mankato.

Wilker, Roger L., 1938-. Oral History Interview, 25 and 30 October 1989. SMHC Manuscript Collection 1406, Southern Minnesota Historical Center, Memorial Library, Minnesota State University, Mankato. https://archivesspace.lib.mnsu.edu/public/repositories/4/resources/498 Accessed April 23, 2024.