Samuel Storrs Howe; et al. (1905). Annals of Iowa. Iowa State Historical Department. p. 155.
Catalogue of Oberlin College for the Year 1890-1891. Oberlin, Ohio: The Oberlin News Free Press. 1890. p. 80. Retrieved June 9, 2009. Link mentions that she found photos of Berthold Matthews at Oberlin in Matthews' belongings, and a Berthold Matthews from Yankton, South Dakota is listed in the 1890 catalog at Oberlin. Presumably Matthews named him after the Fort where he was born.
Powell, J.W. (1888). "Work of Doctor Washington Matthews". Sixth Annual Report of the Bureau of Ethnology to the Director of the Smithsonian 1884–85. Washington, DC: Government Printing Office: XXXVIII–XL.
Link, Margaret Schevill (October–December 1960). "From the Desk of Washington Matthews". The Journal of American Folklore. 73 (290). American Folklore Society: 317–325. doi:10.2307/538492. JSTOR538492.
Matthews, Washington (1898). "Ichthyphobia". The Journal of American Folk-Lore. 11 (41). Published for the American Folk-lore Society by Houghton Mifflin: 105–112. doi:10.2307/533215. JSTOR533215.
Link, Margaret Schevill (October–December 1960). "From the Desk of Washington Matthews". The Journal of American Folklore. 73 (290). American Folklore Society: 317–325. doi:10.2307/538492. JSTOR538492.
Matthews, Washington (1898). "Ichthyphobia". The Journal of American Folk-Lore. 11 (41). Published for the American Folk-lore Society by Houghton Mifflin: 105–112. doi:10.2307/533215. JSTOR533215.