@article {27924,
	title = {Endoparasitic variation between California gulls and Ring-billed gulls Larus californicus and L. delawarensis},
	volume = {111},
	year = {1969},
	pages = {393-395},
	publisher = {Ibis},
	url = {http://www3.interscience.wiley.com/cgi-bin/fulltext/120816446/PDFSTART},
	author = {Vermeer, K.}
}
