Tolong jelaskan mengenai Catatan dari Pikaia

Conway Morris, Simon. 1998. The Crucible of Creation: The Burgess Shale and the Rise of Animals. Oxford University Press, New York, New York.

Gould, Stephen Jay. 1989. Wonderful Life: The Burgess Shale and the Nature of History. W. W. Norton, New York, NY.

Norman, D. (1994) Prehistoric Life: the Rise of the Vertebrates, London: Boxtree

Sheldon, P., Palmer D., Spicer, B. (2001). Fossils and the History of Life. Aberystwyth: Cambrian Printers/The Open University. p. 41-42.