McElroy, Frank S. (Frank Shafer).
Injuries and Accident Causes in the Boilershop-Products Industry : Bulletin of the United States Bureau of Labor Statistics, No. 1237 ,
Washington:
U.S. Dept. of Labor, Bureau of Labor Statistics,
November 1958, https://fraser.stlouisfed.org/title/4505,
accessed on March 20, 2025.