Popov, L. E.; Nikitin, I. F.; Sokiran, E. V. (1999). The earliest atrypides and athyridides (Brachiopoda) from the Ordovician of Kazakhstan. <em>Palaeontology.</em> 42(4): 625-661, 4 plates.[details]
original descriptionPopov, L. E.; Nikitin, I. F.; Sokiran, E. V. (1999). The earliest atrypides and athyridides (Brachiopoda) from the Ordovician of Kazakhstan. <em>Palaeontology.</em> 42(4): 625-661, 4 plates.[details]