- The Psychiatric Interview in Clinical Practice
- Zur Soziologie des Parteiwesens in der modernen Demokratie. Untersuchungen über die oligarchischen Tendenzen des Gruppenlebens
- Roberto Michels' First Lecture in Political Sociology. (Perspectives in social inquiry)
- Political Parties: A Sociological Study of the Oligarchical Tendencies of Modern Democracy
- Political parties;: A sociological study of the oligarchical tendencies of modern democracy