The notion of social structure was extensively developed in the 20th century with key contributions from structuralist perspectives drawing on theories of Claude Lévi-Strauss, as well as feminist, marxist, functionalist (e.g. those developed by Talcott Parsons and followers), and a variety of other analytic perspectives. Some follow Marx in trying to identify the basic dimensions of society that explain the other dimensions, most emphasizing either economic production or political power. Others follow Lévi-Strauss in seeking logical order in cultural structures. Still others, notably Peter Blau, follow Simmel in attempting to base a formal theory of social structure on numerical patterns in relationships—analyzing, for example, the ways in which factors like group size shape intergroup relations.