1. Department of Medical Education; Baskent University Faculty of Medicine; Ankara Turkey
2. Department of Pediatrics; David Geffen School of Medicine at UCLA; Los Angeles CA USA
3. Department of Radiology; University of Pittsburgh Medical Center; Pittsburgh PA USA
4. Department of Pulmonary and Critical Care Medicine; University of Pittsburgh Medical Center; Pittsburgh PA USA
5. Department of Epidemiology; University of Pittsburgh Medical Center; Pittsburgh PA USA