KI closely follows the Vancouver Protocol about authorships. This protocol states that Authorship credit should be based only on substantial contributions to: 
1) conception and design, the acquisition of the data, and/* or analysis and interpretation of data
2) drafting the article or revising it critically for important intellectual content
3) final approval of the version to be published. 

Conditions 1, 2, and 3 must all be met. 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. Any part of an article critical to its main conclusions must be the responsibility of at least one author. 
Authorship order
The order of authorship should be a joint decision of the coauthors. Because the order is assigned in different ways, its meaning cannot be inferred accurately unless it is stated by the authors. Authors may wish to explain the order of authorship in a footnote. In deciding on the order, authors should be aware that many journals limit the number of authors listed in the table of contents and that the U.S. National Library of Medicine (NLM) lists in MEDLINE only the first 24 plus the last author when there are more than 25 authors.
How to deal with authorship issues
If you have a problem regarding authorship of a publication and you and your co-authors cannot come to an agreement, you need to contact the Head of your department. If the Head of your department cannot find a solution, he/she will forward the problem to the Rector. If the rector cannot find a solution, the case will be forwarded to a committee working on Scientific Ethics.
*This is an addition that we found in the KI publication ethics , but not in the Vancouver Protocol.