The document was the "December 1 Act" : Promulgation of the Kingdom of Serbs, Croats and Slovenes (Address of the National Council of Slovenes, Croats and Serbs, December 1, 1918).
The Treaty of Versailles signed in June 1919, which ended World War 1, was an important recognition of what was then the Serbian-dominated "Kingdom of Serbs, Croats, and Slovenes." The colloquial name was Yugoslavia (land of Slavs), and the official name of the state was changed to "Kingdom of Yugoslavia" by King Alexander in 1929.
KOS - Yugoslavia - was created in 1946.
Kingdom of Yugoslavia was created in 1918.
Parliament of Yugoslavia was created in 1946.
Air Yugoslavia was created in 1969.
Live in Yugoslavia was created in 1983.
Return to Yugoslavia was created in 1997-12.
Yugoslavia was created after WW I.
Bishops' Conference of Yugoslavia was created in 1918.
League of Communists of Yugoslavia was created in 1919.
Democratic Party - Yugoslavia - was created in 1918.
Socialist Party of Yugoslavia was created in 1921.
Union of Pioneers of Yugoslavia was created in 1942.