convention or arrangement which may be formulated between two or
more American Republics after this Convention comes into force, the
convention or arrangement most recently formulated shall prevail
between the parties thereto. Rights in works acquired in any
Contracting State under existing conventions or arrangements before the
date this Convention comes into force in such State shall not be
affected.

ARTICLE XIX

This Convention shall not abrogate multilateral or bilateral
conventions or arrangements in effect between two or more Contracting
States. In the event of any difference between the provisions of such
existing conventions or arrangements and the provisions of this
Convention, the provisions of this Convention shall prevail. Rights in
works acquired in any Contracting State under existing conventions or
arrangements before the date on which this Convention comes into force
in such State shall not be affected. Nothing in this Article shall affect
the provisions of Articles XVII and XVIII.

ARTICLE XX

Reservations to this Convention shall not be permitted.

ARTICLE XXI

1. The Director-General shall send duly certified copies of this
Convention to the States interested and to the Secretary-General of the
United Nations for registration by him.