Nordhoff, Sebastian; Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2013). "Permian". Glottolog 2.2. Leipzig: Max Planck Institute for Evolutionary Anthropology. {{cite book}}: Invalid |display-editors=4 (help)
uni-graz.at
languageserver.uni-graz.at
Scheucher, Bernhard. "The Permic Languages". LanguageServer - the Languages of the World. The University of Graz. Archived from the original on 4 March 2016. Retrieved August 22, 2012.
web.archive.org
Scheucher, Bernhard. "The Permic Languages". LanguageServer - the Languages of the World. The University of Graz. Archived from the original on 4 March 2016. Retrieved August 22, 2012.