1. Antunes, M. T., & Mein, P. (1981). Vertébrés du Miocène Moyen de Amor (Leiria), importance stratigraphique. Ciências Da Terra, 6, 169–188.
2. Baumel, J. J., & Witmer, L. M. (1993). Osteologia. In J. J. Baumel, A. S. King, J. E. Breazile, H. E. Evans, & J. C. Vanden-Berge (Eds.), Handbook of avian anatomy (2nd ed., pp. 45–132). Pub Nuttall Ornithol Club.
3. Benson, R. D., & Erickson, B. R. (1997). A new genus and species of Booby (sulidae: aves) from the Pliocene of South Carolina, with a new corollary to the nature of sister taxa. Science Museum of Minnesota, 7, 37.
4. Cachão, M., & da Silva, C. M. (2000). The three main marine depositional cycles of the Neogene of Portugal. Ciências Da Terra (UNL), 14, 303–312.
5. Cohen, A., & Serjeantson, D. (1996). A Manual for the Identification of Bird Bones from Archaeological Sites (p. 99). Archetype Press.