I see that SN for “serial number” is not listed among abbreviations in the documentation. Neither as an abbreviation to use or to avoid.
It is, however, found very often in the variants on german notgeld.
What shall I do - when updating notes that do use SN, i've tended to also use SN - but on other notes with existing variants spelling it out, I've also done the same.
But ideally, I would like for it to be standardized. SN is a very attractive abbreviation as space is often premium in the variant descriptions.
Any thoughts? (I guess the same could be said for KN for Kontrollnummer in german)
Regards
Ernie

