Recommended Reading:
iso_3166:CountryAlpha2CodeType
iso_3166:CountryAlpha3CodeType
iso_3166:CountryNumericCodeType
iso_3166:CountrySubdivisionCodeType
iso_3166:CountryAlpha2CodeSimpleType
iso_3166:CountryAlpha3CodeSimpleType
iso_3166:CountryNumericCodeSimpleType
iso_3166:CountrySubdivisionCodeSimpleType