Steward, Julian H. (1948). "Western Tucanoan Tribes." In Handbook of South American Indians, edited by Julian H. Steward. Vol. 3, The Tropical Forest Tribes, 737-748. Bureau of American Ethnology Bulletin 143. Washington, D.C.: Smithsonian Institution.
Tessmann, Günter (1930). Die Indianer Nordost-Perus. Hamburg: Cram, de Gruyter & Co.
Vickers, William T. (1989). Los sionas y secoyas: Adaptación al ambiente amazónico. Quito: Ediciones ABYA-YALA.