This is the CodeSystem that contains all the codes in ISO 3166-3 Codes for the representation of names of countries and their subdivisions — Part 3: Code for formerly used names of countries (urn:iso:std:iso:3166:-3) and ISO 3166-3 Codes for the representation of names of countries and their subdivisions — Part 3: Code for formerly used names of countries (urn:iso:std:iso:3166:-3). E.g. what you have to deal with if you get resources containing codes in either of them