Shutter, Marion D.; McLaine, J. S., eds. (1897). Progressive Men of Minnesota. The Minneapolis Journal. pp. 318–319. Retrieved February 3, 2023 – via Internet Archive.
newspaperarchive.com
"August T. Koerner". North Vernon Plain Dealer. May 9, 1912. p. 1. Retrieved February 3, 2023 – via NewspaperArchive.