The final version of the PhD dissertation must be written in a national language of the European country where the doctorate is being pursued or in English
(or French, upon authorisation of the Executive Committee). The shorter version written in English (or French, upon authorisation of the Executive Committee) must be in a format that is ready to be submitted to important international journals by the International Evaluation Board of the Final Jury.
In alternative to the “conventional” Thesis format, Research Trainees can adopt the "three papers" PhD thesis format.
A short guide introducing this format is available at: http://europhd.eu/html/_onda01/06/01.00.00.01.shtml