1. Specialist Medical Practice-Pathologist, Non Public Health Care Unit - Department of Pathology (NZOZ Zakład Patologii Spółka z o.o.), Kielce , Poland
2. Department of Public Finances and Financial Law, Faculty of Law , University of Bialystok
3. Department of General Pathomorphology , Medical University of Białystok , Białystok , Poland
4. Department of Nephrology, Dialysis and Internal Medicine , Warsaw Medical University , Warsaw , Poland