Changes to 84/1/Euratom, EEC: Council Decision of 22 December 1983 adopting a research programme to be implemented by the Joint Research Centre for the European Atomic Energy Community and for the European Economic Community (1984 to 1987)
EU Decision 1984/1
Made by 85/373/Euratom: Council Decision of 25 July 1985 complementing Decision 84/1/Euratom, EEC with a view to the realization of a tritium-handling laboratory
From legislation.gov.uk's record of changes, the official one: see it there.