Endocannabinoids, endocannabinoid-like compounds and cortisone in head hair of health care workers as markers of stress and resilience during the early COVID-19 pandemic oleh Ingeborg Biener, Tonina T. Mueller, Jin Lin, Han Bao, Julius Steffen, Marion Hoerl, Katharina Biere, Sandra Matzel, Tobias Woehrle, Simon König, Annekathrin M. Keiler, Detlef Thieme, Oliver Keppler, Matthias Klein, Tobias Weinberger, Andreas Osterman, Kristina Adorjan, Alexander Choukér