World Register of Marine Species (WoRMS)
Schuchert, P.; Choong, H.; Galea, H.; Hoeksema, B.; Lindsay, D.; Manko, M.; Pica, D. (2026). World Hydrozoa Database. Filellum serpens (Hassall, 1848). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=117690 on 2026-08-02
Shidlovskii, A., 1902. Materialy po faune gidroidov arkticheskikh morei. I. Gidroidy Belogo morya u Beregov Solovetskikh ostrovov. Matériaux relatifs à la faune des polypes hydraires des mers arctiques. I. Les Hydraires de la mer Blanche le long du littoral des îles Solowetsky. Trudy Obshch. Ispyt. Prir. imp. Khar'kov Univ. 36 1: 3-268.
Dalyell, J. G. (1847). Rare and remarkable animals of Scotland, represented from living subjects: with practical observations on their nature. By Sir John Graham Dalyell, baronet. John Van Voorst. London. volume 1, pp. v-xii (270 total pages in volume).
Hassall A.H. (1848). Definitions of three new British zoophytes. The Zoologist. 6: 2223.
Thomson, W. T. C., 1853. Notes on some British zoophytes. Annals and Magazine of Natural History -211 : 442-444.
Hincks T. (1855). Notes on British zoophytes, with descriptions of new species. Annals and Magazine of Natural History. 2 (15): 127-130, pls 2-3.