Article 18

The High Contracting Parties agree to apply the principles and rules contained in the preceding articles in their relations with each other, as from the date of the entry into force of the present Convention.

The inclusion of the above-mentioned principles and rules in the Convention shall in no way be deemed to prejudice the question whether they do or do not already form part of international law.

It is understood that, in so far as any point is not covered by any of the provisions of the preceding articles, the existing principles and rules of international law shall remain in force.