1 . COMMON CUSTOMS TARIFF - TARIFF HEADINGS - INTERPRETATION - EXPLANATORY NOTES OF THE CUSTOMS COOPERATION COUNCIL - AUTHORITY 2 . COMMON CUSTOMS TARIFF - TARIFF HEADINGS - INTERPRETATION - EXPLANATORY OF THE CUSTOMS COOPERATION COUNCIL - EXPLANATORY NOTES TO THE COMMON CUSTOMS TARIFF - INTER-RELATIONSHIP 3 . COMMON CUSTOMS TARIFF - TARIFF HEADINGS - MACHINES ' ' FOR CHANGING THE TEMPERATURE AND HUMIDITY OF AIR ' ' WITHIN THE MEANING OF HEADING 84.12 - CONCEPT 4 . COMMON CUSTOMS TARIFF - TARIFF HEADINGS - MACHINES ' ' FOR CHANGING THE TEMPERATURE AND HUMIDITY OF AIR ' ' WITHIN THE MEANING OF HEADING 84.12 - HUMIDITY - CONCEPT - RELATIVE HUMIDITY