1. Dept. of Health Econ.& Mgmt. Science, Mashhad University of Medical Sciences, Mashhad, Iran
2. Department of Anesthesia, Lung Diseases Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
3. Department of Health Management and Economics, Tehran University of Medical Sciences, Tehran, Iran
4. Human Resource Mgmt., Islamic Azad University of North Tehran Branch, Tehran, Iran