Helminen, M. (1958) ”Occurrence of the Red-flanked Bluetail (Tarsiger cyanurus) in Finland and some remarks concerning its expansion to the west”, Ornis Fennica, 35(2–3), s. 51–64. Tillgänglig vid: https://ornisfennica.journal.fi/article/view/132621 (åtkomstdatum: 18maj2024).