Local Catalog Number as Reference Number [Risolto]

Hello,

For many central banks, there is a catalog number for their issues (Russia for example).
So far these are mentioned in the comments section.

Is it possible to add these in the reference field instead?
I have few code numbers for Kuwait coins. These can be added as:
CBK#
Central Bank of Kuwait Code Number

Ok, this can be.

Cita: "Jarcek"​Ok, this can be.

​Great, thanks!
Requested on "New book reference" topic.