1. Sumy State University, Sumy, Ukraine
2. University of Ghana Medical School, Accra, Ghana
3. Northwestern University, Evanston, Illinois
4. Rowan University School of Osteopathic Medicine, Stratford, New Jersey, USA
5. University of Debrecen, Faculty of Medicine, Debrecen, Hungary
6. Faculty of Medicine and Health Sciences, University of Putra Malaysia, Serdang, Malaysia
7. Department of Surgery II, University Hospital Witten-Herdecke, University of Witten-Herdecke, Wuppertal, Germany