Authorship should be limited to those who have made a significant contribution to the manuscript content. All those who have made a significant contribution should be listed as co-authors. It is declared by the author(s) that manuscripts in all categories submitted to the journal and subjected to peer-review have not been published or submitted to any other journal or book. If the manuscript is written by several authors, the corresponding author should be indicated. The corresponding author must on behalf of all the co-authors certify that all of them contributed meaningfully in the preparation of the study, and that the final submitted version of the text is approved by all the co-authors. The author(s) should not publish in their study any copied part of the text and or figures from other sources without proper citation or permission (if necessary) – which is plagiarism. All the authors are obliged to participate in the peer review process, agreeing to the retraction or correction of mistakes as required. The author(s) should indicate in the acknowledgements the financial support and/or programme within which the study has been prepared. Affiliations (all authors/co-authors) and the corresponding address (main author) must be clearly stated.