European Interoperability Framework: Promoting seamless services and data flows [pdf]

Recommendation 1: Ensure that national interoperability frameworks and interoperability strategies are aligned with the EIF and, if needed, tailor and extend them to address the national context and needs.

Recommendation 2: Publish the data you own as open data unless certain restrictions apply.

Recommendation 3: Ensure a level playing field for open source software and demonstrate active and fair consideration of using open source software, taking into account the total cost of ownership of the solution.

...and so on.