The Red Book of the Peoples of the Russian Empire . (1993) · edited by Andrew Humphreys and Krista Mits · http://www.eki.ee/books/redbook

Literacy and the Vernacular in Tajik Badakhshan: Research in Rushani, Khufi, Bartangi, and Roshorvi . Elisabeth Abbess and Katja Müller and Daniel Paul and Calvin Tiessen and Gabriela Tiessen (2010) · http://gamma.sil.org/silesr/2010/silesr2010-015.pdf

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) ·