@book{17949,
	author = {Portnoy, John W. and Erwin, R. Michael. and National Coastal Ecosystems Team (U.S.)},
	title = {Atlas of gull and tern colonies :},
	publisher = {The Team,},
	year = {1981.},
	address = {[Washington, D.C.] :},
	note = {"Biological Services Program"--Portada.}
}