A. R. Freire and A. M. Belchior,  "Ideological representation in Portugal: Congruence between deputies and voters in terms of their left-right placement and its substantive meaning", in Leadership, and Political Representation in Portugal: Essays on Parliament, Media, Voluntary Associations, Parties, Politics, and Voting, André Freire & José Manuel Leite Viegas , Ed., NY, Ed. Edwin Mellen, 2015