We have 2.000 reference catalogues in Numista https://en.numista.com/catalogue/catalogues.php
When we add or modify a coin, banknote or exonumia, have to select the reference catalogue from a endlessly long list of 2000 elements.
I suggest that only the catalogs related to the country appear in the list. Similar to how it was done with currencies.
The initial relation between catalogues and countries can be based on the current use.
