There was also a
French article about these about 60 years ago (by H-G Pflaum in
Revue numismatique, 1959, Volume 6) which I translated and put on the pw-protected page of my
RIC lists page (I can't update my
RIC lists pages here on
Forum because the ftp access changed and mine doesn't
work any more).
If anyone wants a copy of the translation pdf - it's only 202 kb and 12 pages - just send me an email.