Authorship has to be restricted to those who have made a significant contribution to the article preparation like conception, design, execution, or interpretation of the reported study.  All the researchers who have made considerable contributions should be listed as co-authors of the submission.

The other researchers who have participated in certain functional aspects of the paper such as language editing or medical writing should be documented in the acknowledgements section.

The corresponding author should ensure that all appropriate co-authors are listed on the paper, and that all co-authors have seen and permitted the final version of the paper and have agreed for its submission for publication.

The listed authors have to take collective responsibility of the submitted work.  Each individual author is accountable for ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.