CHABAKOV, A.W. (1949)
O dwuch nowych formach problematitschnych iskopayemych Crookallia is karbona Donetzkogo basseyna i Palaeoxyris is jury Krima. [About two new problematic fossils Crookallia from the Carboniferous of Donezk Basin and Palaeoxyris from the Jurassic of Crimea]. Annual of the All–Union Paleontological Society, 13: 83–87, Pl. IX [in Russian].