Willey A (1898) Spengelia, a new genus of Enteropneusta. Quarterly Journal of
Microscopical Science 40: 623-630.[details]
Swalla, B.J.; van der Land, J. (2024). Hemichordata World Database. Spengelia porosa Willey, 1898. Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=266860 on 2024-09-23