1. Department for General and Colorectal Surgery, Medical University of Lodz, Pl. Hallera 1, 90-647 Lodz, Poland
2. Institute for Quality Assurance in Operative Medicine Ltd., Otto-von-Guericke-University, Leipziger Str. 44, D-39120 Magdeburg, Germany
3. Department for Surgery, University Hospital Knappschaftskrankenhaus, Ruhr-University, In der Schornau 23-25, D-44892 Bochum, Germany
4. Department of Economic and Medical Informatics, University of Lodz, 90-214 Lodz, Poland
5. Department of Medical Informatics and Statistics, Medical University of Lodz, 90-645 Lodz, Poland
6. Department for General, Visceral and Vascular Surgery, Otto-von-Guericke-University, Leipziger Str. 44, D-39120 Magdeburg, Germany