This section contains ‘online first’ articles: manuscripts that have been accepted for publication but have not yet been assigned to a particular journal issue. Therefore, the difference between a printed article and an ‘online first’ article is that the latter has no page numbers and no specified issue. This format allows readers to gain access to the newest research outcomes and makes it possible for a paper to be cited earlier. When citing an ‘online first’ article, you should list its author(s), title, journal title, year of publication and DOI.