Coates M.; Gess R.; Finarelli J.; Criswell K.; Tietjen K. A symmoriiform chondrichthyan braincase and the origin of chimaeroid fishes. Nature. 2016, 541: 208–211. PMID 28052054. doi:10.1038/nature20806.
Maisey, John G. The braincase in Paleozoic symmoriiform and cladoselachian sharks. Bulletin of the American Museum of Natural History. 31 October 2007, 307: 1–122. doi:10.1206/0003-0090(2007)307[1:TBIPSA]2.0.CO;2.
Guillaume Guinot; Sylvain Adnet; Lionel Cavin & Henri Cappetta. Cretaceous stem chondrichthyans survived the end-Permian mass extinction. Nature Communications. 2013, 4: Article number: 2669. PMID 24169620. doi:10.1038/ncomms3669.
Coates M.; Gess R.; Finarelli J.; Criswell K.; Tietjen K. A symmoriiform chondrichthyan braincase and the origin of chimaeroid fishes. Nature. 2016, 541: 208–211. PMID 28052054. doi:10.1038/nature20806.
Guillaume Guinot; Sylvain Adnet; Lionel Cavin & Henri Cappetta. Cretaceous stem chondrichthyans survived the end-Permian mass extinction. Nature Communications. 2013, 4: Article number: 2669. PMID 24169620. doi:10.1038/ncomms3669.
Lund R. Harpagofututor volsellorhinus new genus and species (Chondrichthyes, Chondrenchelyiformes) from the Namurian Bear Gulch Limestone, Chondrenchelys problematica Traquair (Visean), and their sexual dimorphism. Journal of Paleontology. 1982., 56: 938–958.请检查|date=中的日期值 (帮助), authorized by John Alroy, Paleobiology Database: Bear Gulch site (页面存档备份,存于互联网档案馆)
Lund R. Harpagofututor volsellorhinus new genus and species (Chondrichthyes, Chondrenchelyiformes) from the Namurian Bear Gulch Limestone, Chondrenchelys problematica Traquair (Visean), and their sexual dimorphism. Journal of Paleontology. 1982., 56: 938–958.请检查|date=中的日期值 (帮助), authorized by John Alroy, Paleobiology Database: Bear Gulch site (页面存档备份,存于互联网档案馆)