- Sá, Artur A.., et all. "Giant trilobites and Other Middle Ordovician Invertebrate Fossils from the Arouca UNESCO Global Geopark, Portugal." Geoconservation Research (Geoconserv. Res.), vol. 4, no. 1, pp. 121-130, https://doi.org/10.30486/gcr.2021.1913689.1057