1. Student Research Club No. 180, Faculty of Medicine, Wroclaw Medical University, 50-367 Wroclaw, Poland
2. Division of Histology and Embryology, Department of Human Morphology and Embryology, Wroclaw Medical University, 50-368 Wroclaw, Poland
3. Department of Surgery, 4th Military Teaching Hospital, 50-981 Wroclaw, Poland
4. Division of Anesthesiological and Surgical Nursing, Department of Nursing and Obstetrics, Faculty of Health Science, Wroclaw Medical University, 51-618 Wroclaw, Poland