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 used systems below.
AIEGL NEW STANDARD
GREpiAbbr: List of Abbreviations of Editions and Works of Reference for Alphabetic Greek Epigraphy. AIEGL, the International Association for Greek and Latin Epigraphy issued a new comprehensive list of abbreviations that will also be used in both SEG and BE. This is now expected to become the new standard
Previous lists may be found at the following places:
SEG has a list at the beginning of each volume, and on their online edition.
The Guide de l’Épigraphiste has a list of abbreviations, available also as a downloadable PDF.
Claros/DGE has an extensive list online.
Epigraphische Datenbank Manfred Clauss has a list that includes Latin inscriptions.
Authoritative lists of abbreviations for general journals for Classics or Archaeology can be found e.g. in L’Année Philologique, the American Journal of Archaeology or the DAI Archäologische Bibliographie. A handy overview of the various systems is provided by the Berkeley library.