Contributors
Submission of multi-authored manuscripts to this journal requires the consent of each author and
all have to sign the covering letter. All authors of, and all contributors (including medical writers and
editors) must specify their individual contributions at the end of the text. The following format is
suggested: 'I declare that I participated in the (here list contributions made to the study) and that
I have seen and approved the final version. I have the following conflicts of interest' (list here all
relevant conflicts and source of funding). This should be listed in the 'Comments' field in EES.