 Complete the following phrase:  Nebojša Jerković, a commander of Mačva Partisan detachment, visited Chetnik captain Dragoslav Račić, a commander of Cer Corp in order to reach agreement on joint attack on Šabac. Battle of Šabac lasted from September 22 until September 24, when 342nd German Division came in aid to besieged Germans and broke rebel encirclement. German soldiers retaliated and killed some 1,000 men from Šabac and Mačva. Number of soldiers in Mačva Partisan detachment drop to half on initial troops. Deployment of 342nd German Division in the Mačva operation marked beginning of 