ISO 3166-3 is part of the ISO 3166 standard published by the International Organization for Standardization (ISO), and defines codes for country names which have been deleted from ISO 3166-1 since its first publication in 1974. The official name of the standard is Codes for the representation of names of countries and their subdivisions – Part 3: Code for formerly used names of countries. It was first published in 1999.
ISO 3166-1 alpha-2 codes are two-letter country codes defined in ISO 3166-1, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), to represent countries, dependent territories, and special areas of geographical interest. They are the most widely used of the country codes published by ISO, and are used most prominently for the Internet's country code top-level domains. They are also used as country identifiers extending the postal code when appropriate within the international postal system for paper mail, and have replaced the previous one consisting one-letter codes. They were first included as part of the ISO 3166 standard in its first edition in 1974.
ISO 3166-2:TL is the entry for East Timor (Timor-Leste) in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:AL is the entry for Albania in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:BG is the entry for Bulgaria in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:MO is the entry for Macao in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
.yu was the Internet country code top-level domain (ccTLD) that was assigned to SFR Yugoslavia in 1989 and was mainly used by Serbia and Montenegro and its two successor states. After Montenegro and Serbia acquired separate .me and .rs domains in 2007, a transition period started, and the .yu domain finally expired in 2010.
UN M49 or the Standard Country or Area Codes for Statistical Use is a standard for area codes used by the United Nations for statistical purposes, developed and maintained by the United Nations Statistics Division. Each area code is a 3-digit number which can refer to a wide variety of geographical and political regions, like a continent and a country. Codes assigned in the system generally do not change when the country or area's name changes, but instead change when the territorial extent of the country or area changes significantly, although there have been exceptions to this rule.
.rs is the Internet country code top-level domain (ccTLD) for Serbia. The domain name registry that operates it is the Serbian National Internet Domain Registry (RNIDS). The letters rs stand for Republika Srbija/Република Србија.
ISO 3166-2:GG is the entry for Guernsey in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:IM is the entry for the Isle of Man in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:JE is the entry for Jersey in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:ME is the entry for Montenegro in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:RS is the entry for Serbia in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:AN was the entry for the Netherlands Antilles in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:AW is the entry for Aruba in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:BA is the entry for Bosnia and Herzegovina in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:MF is the entry for Saint Martin in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
ISO 3166-2:SX is the entry for Sint Maarten in ISO 3166-2, part of the ISO 3166 standard published by the International Organization for Standardization (ISO), which defines codes for the names of the principal subdivisions of all countries coded in ISO 3166-1.
As the state union of Serbia and Montenegro dissolved following the 2006 Montenegrin independence referendum, newly independent Serbia dealt with the issue of assignment of country codes. This task, which could seem trivial, is made hugely complex by the number of countries in the world having names which begin with the letter S. In September 2006, the proposal of the Serbian government to obtain the code RS was accepted by ISO.
Crna Gora 
Srbija 
Vojvodina