1. Medical Research Council Unit; P.O. Box 273 Banjul Gambia
2. University Hospital of Cologne; Cochrane Haematological Malignancies Group, Department I of Internal Medicine; Kerpener Str. 62 Cologne Germany 50924
3. University of Calabar Teaching Hospital; Department of Paediatrics; PMB 1115 Calabar Cross River State Nigeria
4. Oxford University; Clinical Trials Services Unit; Woodstock Road Oxford UK OX2 6HE