@article {35370,
	title = {Biogeographic control of trilobite mass extinction at an Upper Cambrian "Biomere" boundary},
	volume = {13},
	year = {1987},
	pages = {84-99},
	publisher = {Paleobiology},
	url = {http://www.jstor.org/stable/2400840?seq=5},
	author = {Westrop, Stephen R. and Ludvigsen, Rolf}
}
