What is a Macedonian? Who are the Macedonians? And which language did they speak?, MPO convention lecture given by Heinrich Stammler in Cincinatti, Ohio, September, 1987, Box: 5, Folder: 127. Personal Papers of Heinrich Stammler, PP 525. University of Kansas. Kenneth Spencer Research Library. https://archives.lib.ku.edu/repositories/3/archival_objects/164272 Accessed June 23, 2025.