J. N.  Amat and Tempera, F., ?Zoobotryon verticillatum Dell Chiaje, 1822 (Bryozoa), a new occurrence in the archipelago of the Azores (north-eastern Atlantic)?, Marine Pollution Bulletin, vol. 58, pp. 761-764, 2009.

P. J.  Hayward, Ctenostome Bryozoans, vol. 33. London: E.J Brill for the Linnaean Society, 1985.