Indians of North America — Mississippi River Valley -- Antiquities — Audiobooks
Animal Carvings from Mounds of the Mississippi Valley Second Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution, 1880-81, Government Printing Office, Washington, 1883, pages 117-166
by Henry W. (Henry Wetherbee) Henshaw
Ancient Monuments of the Mississippi Valley Smithsonian Contributions to Knowledge, Vol. I.
by E. G. (Ephraim George) Squier, E. H. (Edwin Hamilton) Davis