System theories have been applied to a wide spectrum of empirical cases and policy issues. Parsons and his followers, in particular, applied their systems theory to diverse empirical phenomena in sociology as well as in other disciplines: modernization, economics, politics, social order, industrialization and development, Fascism and McCarthyism, international relations, social change and evolution, complex organizations, health care, universities, religion, professions, small groups, and family as well as abstract questions such as the place of norms in maintaining social order both historically and cross-nationally. Marxian theory and dynamic system theories have also been applied to a spectrum of diverse empirical and policy subjects.

p. 4. - Systems theories (2006)