Attributes / relations provided by
♦ ¹Jorrit H. Poelen, James D. Simons and Chris J. Mungall. (2014). Global Biotic Interactions: An open infrastructure to share and analyze species-interaction datasets. Ecological Informatics.
♦ ²Feeding habits and trophic levels of Mediterranean fish, Konstantinos I. Stergiou & Vasiliki S. Karpouzi, Reviews in Fish Biology and Fisheries 11: 217–254, 2002
♦ ³Diet comparison of four ray species (Raja clavata, Raja brachyura, Raja montagui and Leucoraja naevus) caught along the Portuguese continental shelf, Inês Farias, Ivone Figueiredo, Teresa Moura, Leonel Serrano Gordo, Ana Neves and Bárbara Serra-Pereira, Aquat. Living Resour. 19, 105–114 (2006)