Petrunina, Apollonov & Tschugaeva 1983. [Certain trilobites from boundary deposits of the Cambrian and Ordovician of Batyrbai, Malij Karatau.] Apollonov, M.K.; Bandaletov, S.M.; Ivshin, N.K.[Eds]. The Lower Palaeozoic stratigraphy and palaeontology of Kazakhstan., Nauka, Leningrad, 1983: 1-176. Chapter pagination: 66-90