Peterson KJ, Cotton JA, Gehling JG, Pisani D. (2008). The Ediacaran emergence of bilaterians: congruence between the genetic and the geological fossil records. Philosophical Transactions of the Royal Society B: Biological Sciences363 (1496): 1435–1443. PMID18192191. PMC2614224. DOI: 10.1098/rstb.2007.2233.
Stock, D. & Whitt, G.S. (1992). Evidence from 18S ribosomal RNA sequences that lampreys and hagfish form a natural group. Science257 (5071): 787–9. PMID1496398. DOI: 10.1126/science.1496398.
Peterson KJ, Cotton JA, Gehling JG, Pisani D. (2008). The Ediacaran emergence of bilaterians: congruence between the genetic and the geological fossil records. Philosophical Transactions of the Royal Society B: Biological Sciences363 (1496): 1435–1443. PMID18192191. PMC2614224. DOI: 10.1098/rstb.2007.2233.
Stock, D. & Whitt, G.S. (1992). Evidence from 18S ribosomal RNA sequences that lampreys and hagfish form a natural group. Science257 (5071): 787–9. PMID1496398. DOI: 10.1126/science.1496398.