"congresses and meetings N-O"@en . "congrès et journées d'études N-O"@fr . "congressi, convegni, giornate di studio N-O"@it . "Kongresse und Tagungen N-O"@de . . . . "Ohrid 1961 (xPraxKongrN-O)"@de . . "Ohrid 1961"@de . .