Kjaer, Swen, 1871- , United States. Bureau of Labor Statistics and International Joint Conference Council of the Printing Industry. Survey of Hygienic Conditions in the Printing Trades : Bulletin of the United States Bureau of Labor Statistics, No. 392 , Washington, D.C: G.P.O., September 1925, https://fraser.stlouisfed.org/title/4014, accessed on December 22, 2024.