Nazarov and Rudenko 1981Nazarov, B.B., Rudenko, V.S., 1981. Some bilateral-symmetric Late Paleozoic radiolarians of the South Urals. Questions of Micropaleontology. Vol. 24. Moscow: Nauka Publ. p. 129-139. 1 text-figure, 1 plate (in Russian, res. English).
Acknowledgement to E.O. Amon for doing the scanning and for translating the Russian text into English.