27 between State Parties where the same conditions prevail, or a disguised restriction on international trade, nothing in this Protocol shall be construed as preventing the adoption or enforcement of measures by any State Party that are: (a) necessary to protect public morals or to maintain public order; (b) necessary to protect human, animal or plant life or health; (c) relating to the importations and exportations of gold or silver; (d) relating to the products of prison labour; (e) necessary to secure compliance with laws or regulations which are not inconsistent with the provisions of this Protocol, including those relating to customs enforcement, the protection of patents, trademarks and copyrights, and the prevention of deceptive practices; (f) imposed for the protection of national treasures of artistic, historic or archaeological value; (g) relating to the conservation of exhaustible natural resources if such measures are made effective in conjunction with restrictions on domestic production or consumption; (h) undertaken in pursuance of obligations under any intergovernmental commodity agreement approved by the State Parties; (i) involving restrictions on exports of domestic materials necessary to ensure essential quantities of such materials to a domestic processing industry during periods when the domestic price of such materials is held below the world price as part of a governmental stabilisation plan, provided that such restrictions shall not operate to increase the exports of or the protection afforded to such domestic industry, and shall not depart from the provisions of this Protocol relating to non-discrimination; and (j) essential to the acquisition or distribution of foodstuffs or any other products in general or local short supply, provided that any such measures shall be consistent with the principle that all State Parties are entitled to an equitable share of the international supply of such products, and that any such measures, which are inconsistent with the other provisions of the Protocol shall be discontinued as soon as the conditions giving rise to them have ceased to exist.