1. Unit of Biostatistics; Department of Statistics and Operations Research; School of Medicine, University of Santiago de Compostela; C/San Francisco s/n 15782-Santiago de Compostela Spain
2. Faculty of Psychology and Education Sciences; University of Coimbra; Rua do Colégio Novo, Apartado 6153 3001-802 Coimbra Portugal
3. Faculty of Medicine; University of Coimbra; Rua Larga 3004-504 Coimbra Portugal
4. Chair of Statistics; Georg-August-Universität Göttingen; Platz der Göttinger Sieben 5 37073 Göttingen Germany