1. Bekhterev IA (2000) Encyclopedia of the Orenburg Region. Orenburg Literary Agency, Orenburg, Russia
2. Berdnikov VV (1976) Paleo-cryogenic microrelief in the center of the Russian Plain. Nauka, Moscow, USSR
3. Bertran P, Andrieux E, Antoine P, Coutard S, Deschodt L, Gardère P, Hernandez M, Legentil C, Lenoble A, Liard M, Mercier N (2014) Distribution and chronology of Pleistocene permafrost features in France: database and first results. Boreas 43:699–711. https://doi.org/10.1111/bor.12025
4. Bondarev IV (1978) On thufurs of the Caucasus. In Gorbunov AP (ed) Cryogenic Phenomena of high mountains. Nauka, Siberian Branch, Novosibirsk, USSR, pp 36–42
5. Chibilyov AA (1995) Nature of the Orenburg Region. The South Urals Publishing, Orenburg, Russia