@article {7539,
	title = {A theory of evolution above the species level},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {72},
	number = {2},
	year = {1975},
	note = {PDF},
	pages = {646-650},
	keywords = {bivalvia, evolution, evolutionary theory, macroevolution, mammalia, punctuated equilibrium, selection},
	author = {Stanley, Steven M.}
}
