Harrington, H. J., and A. F. Leanza. “The Classification of the "Olenidae" And the "Ceratopygidae" (Trilobita)”. Revista De La Asociación Geológica Argentina, vol. 7, no. 3, July 1952, pp. 190-06, https://revista.geologica.org.ar/raga/article/view/974.