in Rozova, Biostratigraphy and description of trilobites of the Middle and Upper Cambrian of the north-west of the Siberian platform. Inst. Geol. Geofiz. , Sibirsk Otd. , Akad. Nauk SSSR, Moscow:99; 1965, Uchen. Zap. nauchno-issled. Inst. Geol. Arkt. (Pal
