1. Amoroso, E.C., and L.H. Matthews (1955): Brit. Med. Bull. 11: 87.
2. Anonymous (1970): Metropolitan Life Ins. Stat. Bull. 9 April.
3. Anonymous (1970): Med. World News 11(21:) 15.
4. Personal comunication, Texas State Health Department, Austin, Texas.
5. Anonymous (1940): Vital Statistics of the United States. U.S. Department Health, Education and Welfare, Table 25, Crude death rates for selected causes by month: United States and each State.