Egorova & Pokrovskaya 1962. Cambrian System. Palaeontologieal characteristics of the Cambrian of the Sayan-Altai region. Trilobites Biostratigraphy of the Palaeozoic of the Sayan-Altai mountain region., L. L. Khalfin [ed.], Biostratigraphy of the Palaeozoic of the Sayan-Altai mountain region. I. Lower Palaeozoic. Trud. SNIIGGIMS 19 I960 : 86-93 text-figs. 16-17 [Russian].", 1962: 86-93. Chapter pagination: 86-93