Intraspecies differentiation of winter fur colouring of Pteromys volans (Sciuridae, Mammalia) within its range oleh Sergey N. Gashev, Svetlana G. Babina, Svetlana N. Bondarchuk, Vera K. Vasilyeva, Evgenia P. Vyguzova, Igor V. Zenjko, Alexey V. Krutikov, Elena V. Kulebyakina, Juri P. Kurhinen, Dmitry S. Nizovtsev, Innokentiy M. Okhlopkov, Aleksander P. Savelyev, Natalya V. Sorokina