Mitrus, C., T. H. Sparks, and P. Tryjanowski. “First Evidence of Phenological Change in a Transcontinental Migrant Overwintering in the Indian Sub-Continent: The Red-Breasted Flycatcher Ficedula Parva”. Ornis Fennica, vol. 82, no. 1, Mar. 2005, pp. 13–19, https://ornisfennica.journal.fi/article/view/133627.