Article

Giribet, G., Distel, D.L., Polz, M., Sterrer, W. & Wheeler, W.C. 2000. Triploblastic Relationships with Emphasis on the Acoelomates and the Position of Gnathostomulida, Cycliophora, Plathelminthes, and Chaetognatha: A Combined Approach of 18S rDNA Sequences and Morphology. Syst. Biol. 49(3): 539-562.

Original Classification (root)

([unranked]) Bilateria Hatschek, 1888