FREE MOVEMENT OF GOODS - COMMUNITY TRANSIT - EXTERNAL COMMUNITY TRANSIT - T 1 DOCUMENT - DISCHARGE AT THE OFFICE OF DEPARTURE - EFFECT - RELEASE OF THE GUARANTOR - CONCEPT OF ' ' GUARANTOR ' ' ( ART . 27 ( 3 ) AND THE FIRST PARAGRAPH OF ART . 35 OF REGULATION ( EEC ) NO 542/69 OF THE COUNCIL , AS AMENDED BY REGULATION NO 1079/71 )