CONVENTION OF 27 SEPTEMBER 1968 ON JURISDICTION AND THE ENFORCEMENT OF JUDGMENTS IN CIVIL AND COMMMERCIAL MATTERS - JURISDICTION IN THE CASE OF SALES AND LOANS ON INSTALMENTS - CONCEPT OF ' ' SALE OF GOODS ON INSTALMENT CREDIT TERMS ' ' - INDEPENDENT CLASSIFICATION WITHIN THE CONTEXT OF THE CONVENTION - DESCRIPTION ( CONVENTION OF 27 SEPTEMBER 1968 , ARTS . 13 AND 14 )