Portugese Political Encylopedia
- Bogdanor, Vernon, ed., Coalition Government in Western Europe, Londres, Heinemann Books, 1983.
- Budge, Ian, Agreement and the Stability of Democracy, Chicago, Markham Publishing Co., 1970.
- Idem, com Keman, Hans, Parties and Democracy. Coalition Formation and Government Functioning in Twenty States, Oxford, Oxford University Press, 1990.
- Riker, William H., The Theory of Political Coalitions, New Haven, Yale University Press, 1962.
- Rogowski, Ronald, Commerce and Coalitions. How Trade Affects Domestic Political Alignments, Princeton, Princeton University Press, 1989.
