For convenience, the Roman section has been divided up as follows:
The Portable Antiquities Scheme List of Roman Emporers
Several key online resources:
a) Vols. I and II of the Roman Provincial Coinage series, Link
b) Online Coins of the Roman Empire (OCRE)
Trajan’s Column: detail, lower two registers of frieze on west side, departure of legionaries from their garrison.
BNJ References are listed under the relevant section, but here are some general references on Roman finds (Click)