New Ordovician Nautiloids from Russia. Markovsku, B. P. [Editor] New species of prehistoric plants and invertebrates of the U.S.S.R. pt. 2. Russia., Minist, geol. okh. Nedr S.S.S.R., Moskva", 1960: 123-136. Chapter pagination: 123-136. [Zoological Record Volume 99]