The regulations in some departments allow for the written component of doctoral accomplishments to consist of a number of individual papers. These papers may have been published or not. The combination of papers must represent a complete self-contained description of the research activities carried out and the results obtained.
If candidates in the multi-paper doctoral procedure decide to submit their work in electronic form, they can exclude certain parts that have already been published if the respective publisher does not permit a second publication. For information about which publishers allow second publications under which conditions, see SHERPA/RoMEO.
If permission for second publication is withheld by the publisher, candidates must provide a reference and, if possible, a DOI link to the original article. (Example: The link to the DOI 10.1016/j.ddstr.2007.08.003 would be https://doi.org/10.1016/j.ddstr.2007.08.003) However, the printed copies submitted must comprise the original articles.