1. M.Si., Lecturer, Department of Management, Faculty of Economics and Business, Universitas Muhammadiyah Sumatera Utara
2. M.M., Lecturer, Department of Management, Faculty of Economics and Business, Universitas Muhammadiyah Sumatera Utara
3. M.M., Lecturer, Department of Management, Faculty of Economics and Business, Universitas Muhammadiyah Sumatera Utara, Indonesia