40004953, Marlborough, 59, Portrait (profile right): Julio-Claudian (?). Head of a youth., Walters Art Museum, Baltimore, Boardman, J., Scarisbrick, D., Wagner C., Zwierlein-Diehl, E: The Marlborough Gems (2009), Story-Maskelyne, M.H.: The Marlborough Gems (1870), 42.1039, Cameo, Cornelian