THE MEMBER STATE MAY , HOWEVER , REQUIRE THAT SUCH DIPLOMAS , CERTIFICATES AND OTHER EVIDENCE OF FORMAL QUALIFICATIONS BE ACCOMPANIED BY A CERTIFICATE ISSUED BY THE COMPETENT AUTHORITIES OR BODIES OF THE MEMBER STATE OF ORIGIN OR OF THE MEMBER STATE FROM WHICH THE FOREIGN NATIONAL COMES , STATING THAT HE HAS BEEN ENGAGED IN THE ACTIVITY IN QUESTION AS A SPECIALIST FOR A PERIOD EQUAL TO TWICE THE DIFFERENCE BETWEEN THE LENGTH OF SPECIALIZED TRAINING OF THE MEMBER STATE OF ORIGIN OR OF THE MEMBER STATE FROM WHICH THE FOREIGN NATIONAL COMES AND THE MINIMUM TRAINING PERIOD REFERRED TO IN DIRECTIVE NO 75/363/EEC WHERE THESE PERIODS ARE NOT EQUAL TO THE MINIMUM TRAINING PERIODS LAID DOWN IN ARTICLES 4 AND 5 OF DIRECTIVE NO 75/363/EEC .
IL PEUT CEPENDANT EXIGER QUE CES DIPLOMES , CERTIFICATS ET AUTRES TITRES SOIENT ACCOMPAGNES D'UN CERTIFICAT DELIVRE PAR LES AUTORITES OU ORGANISMES COMPETENTS DE L'ETAT MEMBRE D'ORIGINE OU DE PROVENANCE ATTESTANT L'EXERCICE , AU TITRE DE SPECIALISTE , DE L'ACTIVITE EN CAUSE PENDANT UN TEMPS EQUIVALENT AU DOUBLE DE LA DIFFERENCE EXISTANT ENTRE LA DUREE DE LA FORMATION SPECIALISEE DE L'ETAT MEMBRE D'ORIGINE OU DE PROVENANCE ET LA DUREE MINIMALE DE FORMATION VISEE DANS LA DIRECTIVE 75/363/CEE , LORSQUE CEUX-CI NE SATISFONT PAS AUX DUREES MINIMALES DE FORMATION VISEES AUX ARTICLES 4 ET 5 DE LA DIRECTIVE 75/363/CEE .