Consideration of proposed agreement on the prohibition of the use or threat of use of nuclear weapons against non-nuclear-weapon States parties to the Treaty on the Non-Proliferation of Nuclear Weapons (proposal by Nigeria) : letter dated 7 May 1990 from the Permanent Representative of Nigeria to the United Nations Office at Geneva addressed to the Chairman of the 3rd session of the Preparatory Committee : 4th Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons.