Information from: “North America” (7-41) . Victor Golla and Ives Goddard and Lyle Campbell and Marianne Mithun and Mauricio Mixco (2008) , Chris Moseley and Ron Asher · Routledge
Information from: “The World Atlas of Language Structures” . , Bernard Comrie and David Gil and Martin Haspelmath and Matthew S. Dryer · Oxford University Press