1. Physical-technical quality assurance group, Reference Center Muenster for Mammography at the University Hospital Muenster;
2. Physical-technical quality assurance group, Reference Center for Mammography Southwest in Marburg;
3. Physical-technical quality assurance group, Reference Center for Mammography in Berlin;
4. Physical-technical quality assurance group, Reference Center for Mammography in Munich;
5. Physical-technical quality assurance group, Reference Center for Mammography Nord in Oldenburg;