Regulation (EEC) No 2788/73 of the Commission of 12 October 1973 re-establishing Common Customs Tariff duties on yarn of combed sheep' s or lambs' wool (worsted yarn), not put up for retail sale falling within CCT heading No 53.07 originating in Brazil to which the preferential tariff arrangements set out in Council Regulation (EEC) No 2766/72 of 19 December 1972 apply