BRUA, Robert B; MACHIN, Karen L. Determining and testing the accuracy of incubation stage of Ruddy Duck eggs by floatation. Wildfowl, [S. l.], p. 181–189, 2000. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/153898. Acesso em: 17 dec. 2025.