Eikermann Michaela, Gluud Christian, Perleth Matthias, Wild Claudia, Sauerland Stefan, Gutierrez-Ibarluzea Iñaki, Antoine Sunya-Lee, Demotes-Mainard Jacques, Neugebauer Edmund A M
Institute for Research in Operative Medicine, Faculty of Health, School of Medicine, Witten/Herdecke University, D-51109 Cologne, Germany.
BMJ. 2013 May 7;346:f2771. doi: 10.1136/bmj.f2771.