"Three Types of Variation and Their Relation to Culture Change," in Language, Culture, and Personality: Essays in Memory of Edward Sapir, eds. Leslie Spier, A. Irving Hallowell, and Stanley S. Newman. Menasha, Wis.: George Banta Publishing Co., pp.146-157., 1941, Box: 121, Folder: 16. Morris Edward Opler papers, 14-25-3238. Division of Rare and Manuscript Collections. https://archives.library.cornell.edu/repositories/2/archival_objects/240575 Accessed April 12, 2026.