19.1 Nothing in this Treaty shall preclude any Member State from participating in other arrangements either with other Member States or non-Member States provided that its participation in such arrangements does not derogate from the provisions of this Treaty.
19.2 The rights and obligations arising from agreements concluded before the entry into force of this Treaty between Member States, or between Member States and other countries or organisations, shall not be affected by the provisions of this Treaty.
19.3 To the extent that such agreements in Article 19.2 are not compatible with this Treaty, the Member State or States concerned shall take all appropriate steps to eliminate the incompatibilities established. Member States shall, where necessary, assist each other to this end and shall, where appropriate, adopt a common negotiating position.