1. Institute of Doping Analysis and Sports Biochemistry (IDAS) Dresden; Germany
2. Institute of Legal Medicine of the University of Munich; Germany
3. Institute of Biochemistry/Center for Preventive Doping Research; German Sport University Cologne (DSHS); Germany
4. Fédération Internationale de Football Association (FIFA); Medical Assessment and Research Centre (F-MARC) and Schulthess Clinic; Zurich Switzerland