G.C. Boere, C.A. Galbraith and D.A. Stroud (2006). "Waterbirds around the world"(PDF). Joint Nature Conservation Committee. Archived from the original(PDF) on 2014-06-16. Retrieved 2018-07-25.
Székely, Tamás, John D. Reynolds, and Jordi Figuerola. 2000. Sexual Size Dimorphism In Shorebirds, Gulls, And Alcids: The Influence Of Sexual And Natural Selection. 54(4): 1404-413. [1]
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G.C. Boere, C.A. Galbraith and D.A. Stroud (2006). "Waterbirds around the world"(PDF). Joint Nature Conservation Committee. Archived from the original(PDF) on 2014-06-16. Retrieved 2018-07-25.