Baranov,V.I. et al. (1961)
Fossil flora of Lower Quaternary and Upper Tertiary deposits of the Lower Kama (River) Region [ Iskopaemaya flora Nizhnechetvertichnykhi verkhnetretichnykh otlozheniy Nizhney Kamy. ] Questions of the History of the Quaternary Flora; Materials Relating the Study of the Quaternary Period
Vol. 1 P. 275- 287