Banbura, J., and P. Zielinski. “The Onset of Incubation and Hatching Asynchrony in the Barn Swallow Hirundo Rustica”. Ornis Fennica 72, no. 4 (December 31, 1995): 174–176. Accessed November 25, 2024. https://ornisfennica.journal.fi/article/view/133430.