U.S. Department of Labor. Wage and Labor Standards Administration
U.S. Bureau of Labor Standards , for sale by the Supt. of Docs., U.S. Govt. Print. Off.]1968RevisedSafety in industry. Mechanical and physical hazards series
, Bulletin / Bureau of Labor Standards
222
U.S. Department of Labor. Wage and Labor Standards Administration
U.S. Bureau of Labor Standards , for sale by the Supt. of Docs., U.S. Govt. Print. Off.]1968RevisedSafety in industry. Mechanical and physical hazards series
, Bulletin / Bureau of Labor Standards
216