Polycera quadrilineata. . Site: East Down Yacht Club
 Polycera quadrilineata. Event number: 20230627/01. Site: East Down Yacht Club. 2023-06-27. Photograph © Christine Morrow. (9/25) 
 Christine Morrow (2026). Photograph of Polycera quadrilineata. . Site: East Down Yacht Club. [In] Marine Biodiversity Data Portal - NI.
https://habitas.org/mbdp/sitephoto.php?item=c6272880.jpg. Accessed on 2026-11-03