A number of years ago I picked up a small (15mm) bronze of Geta, as Caesar, from Nicaea in Bithynia. The reverse design features the young Dionysus riding on a panther to the right.
Searching for a catalogue reference, as the particular volume of Roman Provincial Coinage (RPC V.2) is not yet available I had to resort to the older standard catalogues for the series. Waddington's Receuil Générale volume covering Nicaea came up with nothing. Similarly, SNG von Aulock nothing.
The coin proved to have no published reference available. That was the case for over fifteen years until, by chance and looking for something else, I came across the 2004/5 volume of the American Numismatic Journal paper listing new acquisitions of the ANS. There, in the new purchases, was an example of the Geta coin. The accompanying note, reproduced below, acknowledged that no comparable specimen had been found in the references available to them, more prolific than mine.
The, earlier this month I was directed to a, specialised collection being offered at auction later in September. Gorny and Mosch in sale 306 are seeing the collection of Prof. Dr. Wolfram Weiser of coins of Nicaea. Browsing through it there is, at lot 1249, another example of the Dionysus small bronze of Geta (see below) . Yet again they are struggling for a specimen to cite, other than the ANS specimen and choose to reproduce the text of the ANS note.