1. University Hospital of Cologne; Cochrane Haematological Malignancies Group - Department of Internal Medicine 1; Kerpener Str. 62 Cologne Germany 50924
2. University Hospital of Cologne; Department of Internal Medicine 1; Kerpener Str. 62 Cologne Germany 50924
3. German Cochrane Center; Department of Medical Biometry and Statistics; University Medical Center Stefan-Meier-Str. 26 Freiburg Germany D-79104