Lower Oligocene. (In: Stratigraphy of the Mesozoic and Cenozoic of the Western Siberian Lowlands. V.F.Kozyreva, editor)
Foreign title:
Nizhnii Oligotsen. (In-Stratigrafiya Mezozoya i Kainozoya Zapadno-Sibirskoi Nizmennosti. V.F.Kozyreva,editor)
Reference:
Ushakova,M.V. et al. (1957)
Lower Oligocene. (In: Stratigraphy of the Mesozoic and Cenozoic of the Western Siberian Lowlands. V.F.Kozyreva, editor) [ Nizhnii Oligotsen. (In-Stratigrafiya Mezozoya i Kainozoya Zapadno-Sibirskoi Nizmennosti. V.F.Kozyreva,editor) ] Gosudarstyy Soyuznyy Zapadno-Sibirskiy Nefterazvedochnyy Trest
P. 123- 133