Antikainen, E., and V. M. Sorvari. “A Mixed Pair of Yellow Wagtails Motacilla Lutea and M. Flava Flava in Sonkajärvi, North Savo”. Ornis Fennica 62, no. 2 (July 1, 1985): 108. Accessed November 23, 2024. https://ornisfennica.journal.fi/article/view/133184.