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) ·

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

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

Europe and North Asia ( pp. 211-282 ) . Tapani Salminen (2007) · In Encyclopedia of the World's Endangered Languages edited by C. Moseley · London & New York: Routledge

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

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

Permian (Votyak-Zyrien) manual . Austerlitz, R. (1964) · Research and Studies in Uralic and Altaic languages · Vol. 64 · Bell and Howell

Komi-iazvinskii dialekt . Lytkin, V. I. (1961) · Izdatel'stvo akademii nauk, SSSR

Komi-Permyak ( pp. 301-315 ) . Lytkin, V. I. (1966) · In Jazyki narodov SSSR. Volume 3: Finno-ugorskie jazyki i samodijskie jazyki edited by Lytkin, V. I. and Majtinskaja, K. E. · Nauka

Permian ( pp. 249-275 ) . Riese, Timothy (1998) · In The Uralic Languages edited by Abondolo, Daniel · Routledge