As stated in the ICMJE Recommendations, credit for authorship requires:

• Substantial contributions to the conception and design, or the acquisition, analysis, or interpretation of the data;

• The drafting of the article or critical revision for important intellectual content;

• Final approval of the version to be published;

• Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the article are appropriately investigated and resolved.

Authorship credit should be based only on substantial contributions to each of the four components mentioned above.

Participation solely in the acquisition of funding or the collection of data does not justify authorship. General supervision of the research group is not sufficient for authorship. Each contributor should have participated sufficiently in the work to take public responsibility for appropriate portions of the content of the manuscript. The order of naming the contributors should be based on the relative contribution of the contributor towards the study and writing the manuscript. Once submitted the order cannot be changed without written consent of all the contributors. Manuscripts must be submitted by one of the authors of the manuscript, and should not be submitted by anyone on their behalf. The corresponding author takes responsibility for the article during submission and peer review.