1. A. V. Agafonov, “Characteristics of the Acoustic Activity of Beluga Whale by the Results of Audial Analysis,” in Proc. 8th All-Union Conf. for the Study, Protection, and Sustainable Use of Marine Mammals (Astrakhan’: Minist. Rybn. Khoz., 1982), pp. 3–4 [in Russian].
2. A. V. Agafonov, Ya. I. Alekseeva, and V. M. Bel’kovich, “The Investigation of Behavior and Under-water Acoustical Activity of Beluga Whales (Delphinapterus leucas) of the Myagostov Breeding Aggregation,” in Marine Mammals of Holarctic: Collection of Scientific Papers (KMK, Odessa, 2008), pp. 20–24.
3. R. A. Belikov and V. M. Bel’kovich, “The Acoustic Repertoire of the White Sea Beluga (Delphinapterus leucas) in the Solovki Herd Reproductive Aggregation,” in Fundamental Studies of the Oceans and Seas in two books, Ed. by N. P. Laverov (Nauka, Moscow, 2006), pp. 299–337 [in Russian].
4. R. A. Belikov and V. M. Bel’kovich, “High-Pitched Tonal Signals of Beluga Whales (Delphinapterus leucas) in a Summer Assemblage off Solovetskii Island in the White Sea,” Acoustical Physics 52(2), pp. 125–131 (2006).
5. V. M. Bel’kovich, “Beluga Whales of the European North: Recent Studies,” Rybn. Khoz. No. 2, pp. 32–34 (2004) [in Russian].