J. N. C. van der Pers. “Bioerosion by Polydora (Polychaeta, Sedentaria, Vermes) off Helgoland, Germany”. Netherlands Journal of Geosciences (January 1, 1978): 465-478. Accessed April 2, 2026. https://njgjournal.nl/index.php/njg/article/view/14173.