RPC (Roman Provincial Coins)
Burnett, A., M. Amandry, et al. Roman Provincial Coinage. (1992 - ).
RPC I - Burnett, A., M. Amandry and P.P. Ripollès. Roman Provincial Coinage I. From the death of Caesar to the death of Vitellius (44 BC-AD 69). (London, 1992 and 1998 supplement).
RPC II - Burnett, A. and M. Amandry. Roman Provincial Coinage II. From Vespasian to Domitian (AD 69-96). (London, 1999).
RPC VII - Butcher, M. Gordian I to Gordian III (235–8). Province of Asia. (Paris, 2006).
RPC Supp. 2 - Supplement II (2006) by A. Burnett, M. Amandry, P. P. Ripollès, and I. Carradice. (Supplement to Vols. I and II, available in electronic format only, as a 20Mb PDF file)
RPC Online - http://rpc.ashmus.ox.ac.uk/coins/