sentences:  The main tributaries of the Sulm are the Schwarze Sulm ("Black Sulm", long, with Schwanberg as the central market town) and the Weiße Sulm ("White Sulm", long, with Wies) which merge near the village of Prarath, upstream of Gleinstätten.It is there where the actual Sulm valley is considered to begin.Further downstream, near Großklein and Fresing, the Sulm proceeds to receive the Saggau river, and - close to Leibnitz - the Laßnitz river, immediately before the Sulm makes a sharp turn to the Southeast and flows almost parallel to the Mur river before joining it.