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

Ethnologue: Languages of the World, 16th Edition (2009) . (2009) · edited by M. Paul Lewis · SIL International http://www.ethnologue.com/

The World Atlas of Language Structures . (2005) · edited by Bernard Comrie and David Gil and Martin Haspelmath and Matthew S. Dryer · Oxford University Press