"A treatise on surveying, containing the theory and practice: to which is prefixed a perspicuous system of plane trigonometry", by John Gummere, 1841, Box: 1181, Folder: 014. Letter by P.K. Robbins from Ste. Genevieve, May 22, 1835 and Related Book, 2019.014. Special Collections and Archives. https://archivesspace.semo.edu/repositories/2/archival_objects/16902 Accessed November 22, 2024.