Carboneras, Carles (1992): Family Anatidae (Ducks, Geese and Swans). In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.): Handbook of Birds of the World (Volume 1: Ostrich to Ducks): 536–629, plates 40–50. Lynx Edicions, Barcelona. ISBN 84-87334-10-5
Crystal, David (1998): The Cambridge Encyclopedia of Language (Paperback) ISBN 0-521-55967-7
Terres, John K. & National Audubon Society (1991): The Audubon Society Encyclopedia of North American Birds. Wings Books, New York. Reprint of 1980 edition. ISBN 0-517-03288-0
