1. Department of Pharmacy, College of Medicine and Health Sciences, Debre Markos University, P.O. Box 269, Debre Markos, Ethiopia
2. Department of Epidemiology and Biostatistics, Institute of Public Health, College of Medicine & Health Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia
3. Department of Clinical Pharmacy, School of Pharmacy, College of Medicine and Health Science College, University of Gondar, P.O. Box, Ethiopia