United States. Children's Bureau , Springer, Ethel M., 1880- , Byrne, Harriet A. (Harriet Anne), 1892- and Dart, Helen M. (Helen Maretta), 1889-. Child Labor in North Dakota, Bureau Publication No. 129 , Washington, D.C: Government Printing Office, 1923, https://fraser.stlouisfed.org/title/8410, accessed on September 13, 2024.