Changes to Council Regulation (Euratom, ECSC, EEC) No 397/81 of 10 February 1981 fixing the tables of salaries and other components of remuneration consequent on Regulation (Euratom, ECSC, EEC) No 187/81 adjusting the salaries and pensions of officials and other servants of the European Communities and the weightings applying thereto
EU Regulation No 397/1981
Made by Council Regulation (Euratom, ECSC, EEC) No 1974/81 of 13 July 1981 adjusting the weightings applied to the remuneration and pensions of officials and other servants of the European Communities
From legislation.gov.uk's record of changes, the official one: see it there.