 Some forms of reciprocity are thus closely related to redistribution, where goods and services are collected by a central figure for eventual distribution to followers.Marshall Sahlins, an American cultural anthropologist, identified three main types of reciprocity (generalized, balanced and negative) in the book "Stone Age Economics" (1972).Reciprocity was also the general principal used by Claude Lévi-Strauss to explain the "Elementary Structures of Kinship" (1949), in one of the most influential works on kinship theory in the post-war period.