Authors should ensure that where material is taken from other sources (including their own published work), the source is clearly cited and that appropriate permission is obtained.
Authors should not engage in excessive self-citation of their own work.
Authors should not copy references from other publications unless they have read the cited work.
Authors should not predominantly cite their own publications or those of their friends, colleagues, or institutions.
Authors should not quote advertisements or promotional materials.
Editors and reviewers should not ask authors to include citations just to increase the number of citations to their own work or that of a colleague, to the journal or other journal to which they are affiliated.
In accordance with the COPE guidelines, we expect that "original wording taken directly from the publications of other researchers should be enclosed in quotation marks with appropriate references." This condition also applies to the author's own work. COPE produced a discussion paper on citation manipulation with best practice recommendations.