@inbook {Ayala1998_19,
	title = {Origin of the metazoan phyla: Molecular clocks confirm paleontological estimates},
	booktitle = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {95},
	year = {1998},
	pages = {606{\textendash}611},
	author = {Ayala, Francisco Jose and Rzhetsky, Andrey and Ayala, Francisco J.}
}
