Changes made by 77/379/EEC: Commission Decision of 23 May 1977 allowing admission free of Common Customs Tariff duties the scientific apparatus described as 'Lock-in-amplifier' PAR model 128 A, with tuned amplifier PAR model 128 A/98 optional
EU Decision 1977/379
No changes made by 77/379/EEC: Commission Decision of 23 May 1977 allowing admission free of Common Customs Tariff duties the scientific apparatus described as 'Lock-in-amplifier' PAR model 128 A, with tuned amplifier PAR model 128 A/98 optional are recorded.
From legislation.gov.uk's record of changes, the official one: see it there.