I have just seen from my notes that 'Julia' is listed in the 1942-3 Fatelli Giacomasso catalogue. No breeder is given, but the Aicardi varieties are credited to him. The obvious conclusion is that 'Julia' was theirs, as indeed Coggiatti states in his contribution to the Enciclopedia Agraria Italiana.

In the reference of The American Rose Annual, 1948, Julia is listed among roses bred either by Aicardi or by Fr.lli Giacomasso (“This year I decided I must have some new roses and ordered about 20 Italian varieties; they were from Aicardi, the creator of Signora Piero Puricelli, Saturnia, Rome Glory and other roses you know well, or from Giacomasso, the rose firm in Turin which is the Italian Pernet-Ducher.. ... and Julia is small, very free, a charming light warm blend, rather like that good polyantha, Eugene Lamesch.")
As among the roses of the Roseto Botanico “Carla Fineschi” there is a rose named Julia bred by Giacomasso (see references), Giacomasso appears to be the likely “Unknown Italian Breeder(s)” of this rose.