Delarbre C, Gallut C, Barriel V, Janvier P, Gachelin G (фебруар 2002). „Complete mitochondrial DNA of the hagfish, Eptatretus burgeri: the comparative analysis of mitochondrial DNA sequences strongly supports the cyclostome monophyly”. Molecular Phylogenetics and Evolution. 22 (2): 184—92. PMID11820840. doi:10.1006/mpev.2001.1045.
Oisi Y, Ota KG, Kuraku S, Fujimoto S, Kuratani S (јануар 2013). „Craniofacial development of hagfishes and the evolution of vertebrates”. Nature. 493 (7431): 175—80. PMID23254938. doi:10.1038/nature11794.
Janvier P (новембар 2010). „microRNAs revive old views about jawless vertebrate divergence and evolution”. Proceedings of the National Academy of Sciences of the United States of America. 107 (45): 19137—8. PMC2984170. PMID21041649. doi:10.1073/pnas.1014583107. „Although I was among the early supporters of vertebrate paraphyly, I am impressed by the evidence provided by Heimberg et al. and prepared to admit that cyclostomes are, in fact, monophyletic. The consequence is that they may tell us little, if anything, about the dawn of vertebrate evolution, except that the intuitions of 19th century zoologists were correct in assuming that these odd vertebrates (notably, hagfishes) are strongly degenerate and have lost many characters over time.”
Delarbre C, Gallut C, Barriel V, Janvier P, Gachelin G (фебруар 2002). „Complete mitochondrial DNA of the hagfish, Eptatretus burgeri: the comparative analysis of mitochondrial DNA sequences strongly supports the cyclostome monophyly”. Molecular Phylogenetics and Evolution. 22 (2): 184—92. PMID11820840. doi:10.1006/mpev.2001.1045.
Oisi Y, Ota KG, Kuraku S, Fujimoto S, Kuratani S (јануар 2013). „Craniofacial development of hagfishes and the evolution of vertebrates”. Nature. 493 (7431): 175—80. PMID23254938. doi:10.1038/nature11794.
Janvier P (новембар 2010). „microRNAs revive old views about jawless vertebrate divergence and evolution”. Proceedings of the National Academy of Sciences of the United States of America. 107 (45): 19137—8. PMC2984170. PMID21041649. doi:10.1073/pnas.1014583107. „Although I was among the early supporters of vertebrate paraphyly, I am impressed by the evidence provided by Heimberg et al. and prepared to admit that cyclostomes are, in fact, monophyletic. The consequence is that they may tell us little, if anything, about the dawn of vertebrate evolution, except that the intuitions of 19th century zoologists were correct in assuming that these odd vertebrates (notably, hagfishes) are strongly degenerate and have lost many characters over time.”