Kouzov, Sergey, and Anna Loseva. “Modern Distribution, New Breeding and Moulting Places of the Mute Swan (<em>Cygnus olor< Em> Gmelin) in the Leningrad Region in 2005–2015”. Biological Communications, no. 1, Mar. 2016, pp. 116–136, doi:10.21638/spbu03.2016.108.