Widowhood, health, and friendship support in later life.
D000223:Adaptation, Psychological; D000368:Aged / Q000523:psychology*; D005260:Female; D006262:Health; D006304:Health Status; D006801:Humans; D008016:Life Change Events; D008297:Male; D012847:Single Person / Q000523:psychology*; D012931:Social Environment; D012944:Social Support