@article {7486,
	title = {Dating the time of origin of major clades: molecular clocks and the fossil record},
	journal = {Annual Review of Earth and Planetary Sciences},
	volume = {30},
	year = {2002},
	note = {PDF},
	pages = {65-88},
	keywords = {fossils, molecular clock, paleontology, phylogenetics, phylogeny},
	author = {Smith, Andrew B. and Peterson, Kevin J.}
}
