E. Teperoglou and E. Tsatsanis, "The nationalism-postnationalism axis and the gradual transformation of ideological space in Europe: Party discourse trends in six European party systems", in An Audit of Democracy in the European Union, Susan Banducci, Mark Franklin, Heiko Giebler, Sara Hobolt, Michael Marsh, Wouter van der Brug and Cees van der Eijk, Ed., European University Institute, 2012, pp. 241-279