Article 26 1.

The Commission shall take the necessary actions to monitor the effective implementation and compliance with the obligations laid down in Articles 5, 6 and 7 and the decisions taken pursuant to Articles 8, 18, 24, 25 and 29. Those actions may include, in particular, the imposition of an obligation on the gatekeeper to retain all documents deemed to be relevant to assess the implementation of, and compliance with, those obligations and decisions.