Britton, Nathaniel Lord (1859–1934) acknowledgement of contribution to Bessey, Charles E. (1845–1915), 6 April 1889, Box: 1, Folder: 2. William Winfield Ray collection of 20th century botanists correspondence and other materials, HIBDARC-0048. Hunt Institute for Botanical Documentation Archives. https://as.huntbot.org/repositories/2/archival_objects/3567 Accessed March 20, 2026.