United States. Children's Bureau , Matthews, Ellen N., 1884- and Light, Gertrude Underhill, 1871-. Child Labor and the Work of Mothers in the Beet Fields of Colorado and Michigan, Bureau Publication No. 115 , Washington, D.C: Government Printing Office, 1923, https://fraser.stlouisfed.org/title/8397, accessed on October 10, 2024.