Everything depends on whether they are mentioned by Greek and Latin authors (who in quoting or copy second hand may have altered some names), or used in other written sources, mostly inscriptions and routes, that of Celtic names report either adaptations (and alterations) operated by different Latin speakers or those adopted by the Roman state, in its different parts and historical phases.
The third group includes Gallo-Roman land (rustic names of terrains) or predial toponyms, formed by an ancient anthroponym (but not always Celtic) and one of the Gaulish suffixes -ācum, -āca, -īcum, -īca.
It is a group that was productive in the early Middle Ages too, when predials with Celtic suffix from Germanic anthroponyms were born.
This especially where -ate, or sometimes -ato, They may have replaced an older Celtic predial suffix; for example in the case of Lovernato: *Lovernaco (vico Luernaco, attested in 807), from personal name *Louernus (Louernius or Louernacus) < louernos ‘fox’.
In his articles Pellegrini lists several appellatives that are derived from these toponyms: «beccus, betulla, broga, brogilos, brūcus, cumbo, *camminus, cumba, *glasina, *lanca, ligita, nantu, *pettia, *rica, *tamisium, *tegia, verna ecc.», ambli and *barros.