Changes made by 83/671/EEC: Commission Decision of 12 December 1983 relating to a proceeding under Article 85 of the EEC Treaty (IV/30.525 - International Energy Agency) (Only the English, German and French texts are authentic)
EU Decision 1983/671
No changes made by 83/671/EEC: Commission Decision of 12 December 1983 relating to a proceeding under Article 85 of the EEC Treaty (IV/30.525 - International Energy Agency) (Only the English, German and French texts are authentic) are recorded.
From legislation.gov.uk's record of changes, the official one: see it there.