1. Dahl, Robert A., Who Governs? Democracy and Power in an American City. New Haven, 1961.
2. Downs, Anthony, An Economic Theory of Democracy. New York, 1957.
3. Lane, Robert E., Political Involvement Through Voting. In: B. Seasholes (ed.) Voting, Interest Groups, and Patries. Glenview (Ill.) 1966.
4. Milbrath, Lester W., Political Participation. How and Why Do People Get Involved in Politics? Chicago, 1965.