1. Center for Preventive Doping Research, Institute of Biochemistry, German Sport University Cologne, Am Sportpark Muengersdorf 6, 50933, Cologne, Germany
2. Organic Chemistry Institute, Westfälische Wilhelms-Universität Münster, Münster, Germany
3. Institute for Organic Chemistry, University of Cologne, Cologne, Germany
4. Antidoping Switzerland, Berne, Switzerland