1. Department of Paediatrics; Hospital Vila Franca de Xira; Vila Franca de Xira Portugal
2. Department of Paediatrics; Hospital Garcia de Orta; Almada Portugal
3. Unit of Paediatric Haematology; Department of Paediatrics; Hospital de Santa Maria; Centro Hospitalar Lisboa Norte; EPE; Lisboa Portugal
4. Laboratory of Biomathematics; Faculdade de Medicina de Lisboa; Lisboa Portugal