Regulation (EEC) No 940/73 of the Commission of 5 April 1973 reintroducing Common Customs Tariff duties on yarn of carded sheep' s or lambs' wool (woollen yarn), not put up for retail sale, falling within heading No 53.06, originating in developing countries to which the preferential tariff arrangements set out in Council Regulation (EEC) No 2766/72 of 19 December 1972 apply