COSTANZO I, CLORO – Bronze head (3rd–4th century).
Munich, Glyptothek.
s. V. in Pauly-Wissowa, VII, cols. 1044–94; id., Regesten der Kaiser und Pöpste (1919). For the rest, one must consult works of a general nature, such as Fliche-Martin-Fruta, III, nos. 105–69; V. also the bibliography of the entries ABIANESIMO; ATANASIO, santo; LIBERIO. Ludovico Hertling