BARTOLOMAEUS, T. Chaetogenesis in polychaetous Annelida-Significance for annelid systematics and the position of the Pogonophore. Zoology. 1997, 100, 348-364
BOORE, JL. Mitochondrial genomes of Galathealunum, Helobdella, and Platynereis : Sequence and gene arrangement comparisons indicate that pogonophore is not a phylum and annelida and arthropoda are not sister taxa. Mol Biol Evol. 2000, 17, 1, 87-106
DALES, RP. The polychaetae stomodeum and the inter-relationships of the families of polychaeta. Proc Zool Soc London. 1962, 139, 389-428