Napríklad aj tých stránkach ISO, ktoré som linkol:
Citácia:
The country codes can be represented either as a two-letter code (alpha-2) which is recommended as the general purpose code, a three-letter code (alpha-3) which is more closely related to the country name and a three digit numeric code (numeric -3) which can be useful if you need to avoid using Latin script.
Alebo aj tu:
http://publications.europa.eu/code/sk/sk-370100.htm
