Monge-Nájera, J. and Hou, X. (2000) “Disparity, decimation and the Cambrian "explosion": comparison of eady Cambrian and Present faunal communities with emphasis on velvet worms (Onychophora)”, Revista de Biología Tropical, 48(2-3), pp. 333–351. doi: 10.15517/rbt.v48i2-3.18718.