 At the medieval ruins of the town of Zvezdangrad, the Studva becomes a border river between Croatia and Serbia (total length as a border or Serbian river is 18 km).At the village of Morović the Studva empties into the Bosut river.Just like the Bosut itself, the Studva is a satellite flow to the Sava river and uses the same, ancient (fossile) Sava's river bed.