1. V. A. Yudkin, Birds of the Subtaiga Forests in West Siberia (Nauka, Novosibirsk, 2002) [in Russian].
2. Ts. Z. Dorzhiev, in Fauna and Ecology of Birds in East Siberia (Irkutsk, 1984), pp. 26–33 [in Russian].
3. I. V. Prokof’eva, in Ecology of Birds in the Reproductive Period (Leningrad, 1985), pp. 29–39 [in Russian].
4. O. A. Shemyakina, E. A. Marochkina, I. V. Zatsarinnyi, and N. V. Chel’tsov, Russ. Ornitol. Zh. 16(362), 759 (2007).
5. E. S. Preobrazhenskaya, Ecology of Passerines of the Vetluga Region (KMK Scientific Press, Ltd., Moscow, 1998) [in Russian].