Conway Morris, S.; Caron, J. B. (2012). "Pikaia gracilens Walcott, a stem-group chordate from the Middle Cambrian of British Columbia". Biological Reviews 87: 480-512.DOI:10.1111/j.1469-185X.2012.00220.x
Lacalli T. (2012) "The Middle Cambrian fossil Pikaia and the evolution of chordate swimming". EvoDevo (journal)3: 12. DOI:10.1186/2041-9139-3-12
Mallatt, J.; Holland, N. D. (2013). "Pikaia gracilens Walcott: stem chordate, or already specialized in the Cambrian?". Journal of Experimental Zoology, Part B, Molecular and Developmental Evolution.DOI:10.1002/jez.b.22500
Stach T. (2008) "Chordate phylogeny and evolution: a not so simple three-taxon problem". Journal of Zoology V.276. I.2: 117-141.DOI:10.1111/j.1469-7998.2008.00497.x
