Translated as "Polarization, Fragmentation and Competition in Western Democracies." H. Daalder and P. Mair (eds.), West European Party Systems: Continuity and Change. London: Sage, 1983, pp. 307-340; and in Revista de Ciencia Polìtica (Chile), 1-2, 1991. Also published in Universidad Nacional de Educaciòn a Distancia, Madrid, Fall, 1980