1. School of Mathematics and Statistics; University of Glasgow; Glasgow G12 8QW U.K.
2. Department of Mathematics and Statistics; University of Strathclyde; Glasgow G1 1XH U.K.
3. Competence Center for Methodology and Statistics; CRP-Santé, 1a rue Thomas Edison; 1445 Strassen Luxembourg
4. ICON Clinical Research UK Ltd; 2 Globeside, Globeside Business Park; Marlow Buckinghamshire SL71TB U.K.