Moura, T. & Figueiredo, I. & Farias, I. & Serra-Pereira, B. & Coelho, R. & Erzini, K. & Neves, A. & Serrano-Gordo, L. (2007)
The use of caudal thorns for ageing Raja undulata from the Portuguese continental shelf, with comments on its reproductive cycle.
Marine and Freshwater Research, 58(11), 983–992 DOI: 10.1071/MF07042