1. Garstang, W., The morphology of the Tunicata and its bearing on the phylogeny of the Chordata, J. of the Microscopical Society, 1928, 72: 51–87.
2. Berrill, N. J., The Origin of Vertebrates, Oxford Oxford University Press, 1955.
3. Romer, A. S., The Vertebrate Story, Chicago: University of Chicago Press, 1971.
4. Schaeffer, B., Deuterostome monophyly and phylogeny, Evoln. Biol., 1987, 21: 179–235.
5. Gee, H., Deuterostome phylogeny: The context for the origin and evolution of the vertebrates, in Major Events in Early Vertebrate Evolution: Palaeontology, Phylogeny, Genetics and Development (ed Ahlberg, P. E.), London and New York: Taylor and Francis Inc., 2001.