@article {6374,
	title = {The disparity of the Burgess Shale arthropod fauna and the limits of cladistic analysis: why we must strive to quantify morphospace},
	journal = {Paleobiology},
	volume = {17},
	number = {4},
	year = {1991},
	note = {PDF},
	pages = {411-423},
	keywords = {constraints, evolution, theoretical morphology},
	author = {Gould, S. J.}
}
