@book {2208,
	title = {Mute Swan (Cygnus olor). In The Birds of North America No 273 },
	year = {1997},
	publisher = {The Birds of North America, Inc.},
	organization = {The Birds of North America, Inc.},
	edition = {No. 273 (A.Poole and F. Gill) },
	address = {Philadelphia, PA},
	author = {Ciaranca, M. A. and Allin, CC and Jones, GS}
}
@book {2207,
	title = {The descent of man, and selection in relation to sex.},
	year = {1871},
	author = {Darwin, C. R.}
}
