Watanabe, J., & Matsuoka, H. (2015). Flightless diving duck (Aves, Anatidae) from the Pleistocene of Shiriya, northeast Japan. Journal of Vertebrate Paleontology, 35(6), e994745. https://doi.org/10.1080/02724634.2014.994745
Watanabe, J. (2017). Quantitative discrimination of flightlessness in fossil Anatidae from skeletal proportions. The Auk, 134(3), 672–695. https://doi.org/10.1642/auk-17-23.1
E. Marjorie Northcote. Size, form and habit of the extinct Maltese Swan Cygnus falconeri. „Ibis”. 124 (2), ss. 148–158, 1982. doi:10.1111/j.1474-919X.1982.tb03753.x.