Complex sentence: In September 1991, Bosnian Serbs proclaimed a Serbian Autonomous Oblast with Bijeljina as its capital, and in March 1992, the Bosnian referendum on independence was passed with overwhelming support from Bosniaks and Bosnian Croats.
Split into simpler sentences: In September 1991, Bosnian Serbs proclaimed a Serbian Autonomous Oblast with Bijeljina as its capital. In March 1992, the Bosnian referendum on independence was passed with overwhelming support from Bosniaks and Bosnian Croats.