Michael Schwenk*, Andreas Lauenroth, Christian Stock, Raquel R Moreno, Peter Oster, Gretl McHugh, Chris Todd and Klaus Hauer
* Corresponding author: Michael Schwenk mschwenk@bethanien-heidelberg.de
BMC Medical Research Methodology 2012, 12:50 doi:10.1186/1471-2288-12-50