Iulius' praenomen Vopiscus appears in Liv., Dion. Hal., and Lib. de Praenominibus 2; the cognomen Iulus is preserved in Fast. Cap. In Diod. the name appears as {Gr}. (Broughton MRR I)
Liv. 2.54.3; Diod. 11.65.1; Fast. Cap. ([- - - -] Iulus); Dion. Hal. 9.37.1, and 41.1; Chr. 354 (Mamerco III et Volsco); Fast. Hyd. (Aemilio et Iulio); Chr. Pasc. ({Gr}); and on Aemilius, Cassiod.; see Degrassi 24f., 90, 358f. (Broughton MRR I)