Walter M. Sandruk has released one of his papers dealing with early Christian inscriptions. You can download either the one with pictures or the one without pics. Here's his abstract:
Christian inscriptions of the first three centuries furnish an important source of evidence for early Christian faith. “A Brief Survey of Early Christian Inscriptions as Witnesses to Christian Faith” begins with an overview of early Christian symbols and abbreviations, especially those found in Roman catacombs, and discusses the difficulties of distinguishing inscriptions as Christian as opposed to Jewish or Pagan. The discussion next turns to the controversial “Jesus” inscriptions discovered by E. L. Sukenik in 1945, continues onto Montanist inscriptions and ends with Avercius’ epitaph. The essay is not exhaustive by any means, but offers a beginning point of research for those interested in Christian epigraphy, especially the controversial, and perhaps earliest, Christian inscriptions uncovered by Sukenik.We went over a couple inscriptions in the forum here and I suggest looking at that as well.