Changes made by 80/256/EEC: Commission Decision of 14 December 1979 relating to a proceeding under Article 85 of the EEC Treaty (IV/29.595 - Pioneer Hi-Fi Equipment) (Only the French, German, English and Dutch texts are authentic)
EU Decision 1980/256
No changes made by 80/256/EEC: Commission Decision of 14 December 1979 relating to a proceeding under Article 85 of the EEC Treaty (IV/29.595 - Pioneer Hi-Fi Equipment) (Only the French, German, English and Dutch texts are authentic) are recorded.
From legislation.gov.uk's record of changes, the official one: see it there.