Patterns of democracy: government forms and perfomance in thirty-six countries: Arend Lijphart1999Lijphart, A. (1999). Patterns of democracy: government forms and performance in thirty six countries. New Haven: Yale University Press.
Teoria das formas políticas e dos sistemas de governo: João Reis Novais2017Novais, J. R. (2017). Teoria das formas políticas e dos sistemas de governo. Lisboa: AAFDL Editora.
Parliamentary versus presidential government: Arend Lijphart (Ed.)1998Lijphart, A. (Ed.) (1998). Parliamentary versus presidential government. New York: Oxford University Press.
Xeque-mate, análise comparativa dos sistemas políticos semi-presidenciais: Maurice Duverger1979Duverger, M. (1979). Xeque-mate: análise comparativa dos sistemas políticos semi-presidenciais. Lisboa: Edições Rolim.
Presidentes e (semi)presidencialismo nas democracias contemporâneas: estudos inéditos: António Costa Pinto e Paulo Canelas Rapaz2018Pinto, A.C. & Rapaz, A.C. (2018). Presidentes e (semi)presidencialismo nas democracias contemporâneas: estudos inéditos. Lisboa: Instituto de Ciências Sociais.
Direito constitucional: as instituições do estado democrático e constitucional.: Cristina Queiroz2009Queiroz, C. (2009). Direito constitucional: as instituições do estado democrático e constitucional. Coimbra: Coimbra Editora.
Secundária
The british system of government: Anthony H. Birch2003Birch, A.H. (2003). The british system of government. London: Routledge.
Bitter Harvest: FDR, presidential power and the growth of the presidential branch.: Matthew J. Dickinson1999Dickinson, M.J. (1999). Bitter harvest: FDR, presidential power and the Growth of the presidential branch. Cambridge: Cambridge University Press.
Coalitional presidentialism in comparative perspective: minority presidents in multiparty systems.: Paul Chaisty, Nick Cheeseman e Timothy J. Power2018Chaisty, P., Cheeseman, N. & Power, T.J. (2018). Coalitional presidentialism in comparative perspective: minority presidents in multiparty systems. New York: Oxford University Press.
The american political process: Alan Grant2004Grant, A. (2004). The american political process. London: Routledge.
Veto bargaining: presidents and the politics of negative power: Charles M. Cameron2000Cameron, C.M. (2000). Veto bargaining: presidents and the politics of negative power. Cambridge: Cambridge University Press.