Commission Regulation (EEC) No 2793/83 of 6 October 1983 amending Regulations (EEC) No 1107/68, (EEC) No 2496/78, (EEC) No 1402/83 and (EEC) No 1441/83 with regard to the detailed rules for the granting of private storage aid for Grana Padano, Parmigiano Reggiano, Provolone, Pecorino Romano and other long-keeping cheeses