One of the peculiarities of the epigraphic profession is the use of arcane abbreviations and acronyms for the various publications. You can find a number of commonly uses systems below. Please don't invent your own system, but use one that has found common acceptance, and stick to it.
The Guide de l'Épigraphiste has a list of abbreviations, available also as a downloadable PDF.
Claros/DGE has an extensive list on-line.
Epigraphische Datenbank Manfred Clauss has a list that includes Latin inscriptions.
Authoritative lists of abbrevations for general Classics or Archaeology journals can be found e.g. in L'Année Philologique, (for a PDF click here) the American Journal of Archaeology or the DAI Archäologische Bibliographie.