1. N. A. Aksarina and Yu. L. Pelman, Cambrian Brachiopods and Bivalves of Siberia (Nauka, Moscow, 1978) [in Russian].
2. W. C. Bell, “Cambrian Brachiopoda from Montana,” J. Paleontol. 15(3), 193–255 (1941).
3. G. Biernat, “Ordovician Inarticulate Brachiopods from Poland and Estonia,” Palaeontol. Polon., No. 28, 1–120 (1973).
4. A. Boucot, Evolution and Extinction Rate Controls (Elsevier, Amsterdam, 1975).
5. A. G. Boucot, Chen Xu, and C. R. Skotese, “Phanerozoic Climatic Zones and Paleogeography with a Consideration of Atmospheric CO2 Levels,” Paleontol. Zh., No. 2, 3–11 (2004) [Paleontol. J. 38 (2), 115–122 (2004)].