When is it time to die?  Prolegomenon to voluntary euthanasia.
D001293:Attitude to Death; D001926:Brain Death; D002908:Chronic Disease; D003643:Death; D004463:Ecology; D005065:Euthanasia; D033101:Euthanasia, Active, Voluntary; D005066:Euthanasia, Passive; D006801:Humans; D008017:Life Expectancy; D008020:Life Support Care; D011788:Quality of Life; D012297:Right to Die; D012649:Self Concept; D012959:Socioeconomic Factors; D013405:Suicide; D019452:Terminally Ill