Regulation (EEC) No 1598/73 of the Commission of 14 June 1973 re-establishing Common Customs Tariff duties on flax or ramie yarn, not put up for retail sale, falling within heading No 54.03, originating in developing countries to which the preferential tariff arrangements set out in Council Regulation (EEC) No 2766/72 of 19 December 1972 apply