An article by Inteo lawyer Kristof Neefs was published in the peer-reviewed legal journal Tijdschrift voor Belgisch Handelsrecht. Kristof comments on the application of the Sieckmann criteria for the representation of trade marks in the register by the EU General Court in joined cases T-101/15 and T-102/15 (Red Bull). The case comment includes an overview of EU and Belgian case law on the requirement of representation of a mark. After publication, the EU Court of Justice seemingly has extended those criteria to copyright in case C-310/17.
The article (in the Dutch language) can be consulted here.