Citizens of Montenegro, the mountainous, sparsely populated former Yugoslav territory, will vote Sunday in a referendum on severing its remaining links with Serbia. The pro-independence camp is confident of victory. The referendum will determine whether the state of Serbia and Montenegro continues to exist. That loose federation - replacing the rump Yugoslavia - was created three years at the strong urging of the European Union, which at the time opposed the Montenegrin government's desire to break with Serbia. Since both Serbia and Montenegro wish to join the EU, Brussels has been deeply involved in the May 21 referendum. Under its...