Article 4
1. Each NSA shall supply the Agency with the information necessary to compile the national reference document. In particular the NSA shall: (a) supply the Agency with references to national rules for each parameter and their classification; (b) advise the Agency of changes to the rules at the time of publication of the change of rule; (c) nominate a person or a department which will be responsible for the supply of this information to the Agency; (d) conduct an active exchange of views and experiences with other NSAs in order to be able to classify the rules in accordance with Article 3(1)(b). NSAs shall cooperate with a view to eliminating unnecessary requirements and redundant verifications. 2. Each Member State shall approve its national reference document. 3. Within 1 year of the publication of the relevant national reference document, Member States shall ensure consistency between the requirements contained in the reference document and the requirements contained in rules notified pursuant to Article 17 of Directive 2008/57/EC. Once a single data entry for the notification of national rules and for the reference document is available, the deadline to ensure consistency between them shall be 6 months. The Commission shall inform Member States of the date by which the single data entry for notification of national rules is available. After this period if the Agency becomes aware of an inconsistency it shall advise the relevant Member State. Where a rule of the reference document is not yet notified either that rule shall be notified or the reference document shall be updated. 4. Member States shall notify to the Commission within 2 months of entry into force of this Decision the competent department which will be in charge of validating and approving their national reference document and changes thereto.