Fox, Anthony D., Jørgen P. Kjeldsen, Mark Desholm, Palle A.F. Rasmussen, Thorsten J.S. Balsby, and Henning Heldbjerg. “Within and Between Year Phenology of Calling Spotted Crakes Porzana Porzana in Denmark”. Wildfowl (November 27, 2014): 102–115. Accessed December 16, 2025. https://tidsskrift.dk/Wildfowl/article/view/153632.