1. Department of General Surgery, Ankara Training and Research Hospital, Ankara, Turkey
2. Department of General Surgery, Ankara Atatürk Training and Research Hospital, Ankara, Turkey
3. Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
4. Department of Biochemistry, Etimesgut Public Health Laboratory, Ankara, Turkey
5. Department of General Surgery, Gemerek State Hospital, Sivas, Turkey
6. Department of General Surgery, Siverek State Hospital, Şanlıurfa, Turkey
7. Faculty of Medicine, Department of Biostatistics, Hacettepe University, Ankara, Turkey