Hi,
The title was "Aspects of the Relationship Between the Central and Gallic Empires in the Mid to Late Third Century AD". It is available as a monograph in the British Archaeological Reports International Series, No. 963 (2001).
It is an examination of, amongst other things, the changing composition of Gallic
hoards and the movement of Central Empire coin into them.
There are also chapters on the bronze coinage of
Postumus, Gallic Empire gold, immitations, Gallic inscriptions and a general
history of the period.
Regards,
Mauseus