United States. Children's Bureau , Duncan, Beatrice Sheets and Duke, Emma, 1876-. Infant Mortality : Results of a Field Study in Manchester, N.H. Based on Births in One Year, Infant Mortality Series No. 6, Bureau Publication No. 20 , Washington, D.C: Government Printing Office, 1917, https://fraser.stlouisfed.org/title/8313, accessed on December 26, 2025.