List of Articles Selam Yibeltal Article 1 - Service Performance Improvement Model: The Case of Teklehaymanot General Hospital 20.1001.1.22519904.2018.11.1.2.2 10.22094/joie.2017.716.1452 Eshetie Berhan Selam Yibeltal Sisay Geremew Journal of Optimization in Industrial Engineering , Issue 23 , Year , Spring 2018