Vatican document confirms there is Vicarivs Filii Dei

The title appears in volume 99, page 21, in the entry for VICARIO DI GESU' CRISTO [Vicar of Jesus Christ], where it states very briefly that the

inscription VICARIUS FILII DEIis to be found in the VATICAN.

— Dizionario di erudizione storico-ecclesiastica da S. Pietro sino ai nostri giorni (Dictionary of Historical-Ecclesiastical Erudition from St. Peter to the Present), Gaetano Moroni