Endangered Languages Catalogue Project. Compiled by research teams at University of Hawai'i Mānoa and Institute for Language Information and Technology (LINGUIST List) at Eastern Michigan University . (2012) ·

World Oral Literature Project . http://www.oralliterature.org

Atlas of the World’s Languages in Danger . Christopher Moseley (ed.) (2010) · UNESCO Publishing http://www.unesco.org/culture/en/endangeredlanguages/atlas

Ethnologue: Languages of the World, 18th Edition . (2015) · edited by Lewis, M. Paul, Gary F. Simons, and Charles D. Fennig · SIL International http://www.ethnologue.com

Some language and sociolinguistic relationships in the Upper Sepik region of Papua New Guinea ( pp. 243-273 ) . Conrad, Robert J. and Ronald K. Lewis (1988) · In Papers in New Guinea Linguistics 26 Pacific Linguistics: Series A · Vol. 76 · Canberra: Research School of Pacific and Asian Studies, Australian National University