Article 3
1. By 31 December 2019, Member States shall adopt and publish the measures necessary to comply with this Directive. They shall immediately inform the Commission thereof. They shall apply those measures from 1 January 2020. When Member States adopt those measures, they shall contain a reference to this Directive or shall be accompanied by such a reference on the occasion of their official publication. The methods of making such reference shall be laid down by Member States. 2. Member States shall communicate to the Commission the text of the main measures of national law which they adopt in the field covered by this Directive.