Sociologists Please Help.Need definitions for different types of family structures for eg Nucler,Joint and Ext

Question

Hello!!I am writing a paper and i need exact definitions for Nuclear family,Joint family and Extended family?Exact definitions and Credible sources(read not wikipedia) would be very much appreciated.Will give ten points to the best answer.Please help!!Thank you!!!

Answer 1

also called elementary family in sociology and anthropology, a group of persons united by ties of marriage and parenthood or adoption and consisting of a man, a woman, and their socially recognized children. This unit was once widely held to be the most basic and universal form of social organization. Anthropological research, however, has illuminated so much variability of this form that it is…

nuclear family
http://www.britannica.com/eb/article-9056440/nuclear-family

an expansion of the nuclear family (parents and dependent children), usually built around a unilineal descent group (i.e., a group in which descent through either the female or the male line is emphasized). The extended family system often, but not exclusively, occurs in regions in which economic conditions make it difficult for the nuclear family to achieve self-sufficiency.

extended family
http://www.britannica.com/eb/article-9033456/extended-family

family in which members of a unilineal descent group (a group in which descent through either the female or the male line is emphasized) live together with their spouses and offspring in one homestead and under the authority of one of the members. The joint family is an extension of the nuclear family (parents and dependent children), and it typically grows when children

joint family
http://www.britannica.com/eb/article-9043892/joint-family