Conversion table of code and title changes, third to fourth edition, Dictionary of occupational titl

United States Employment Service.
Washington : The Service : For sale by the Supt. of Docs., U.S. Govt. Print. Off., 1979.

Dictionary of occupational titles : fourth edition supplement, 1986.

[Washington, D.C.?] : U.S. Dept. of Labor, Employment and Training Administration : [Supt. of Docs., U.S. G.P.O., distributor], 1986 [that is, 1987]

Early America at work; a pictorial guide to our vanishing occupations.

Wilson, Everett Broomall, 1900-
New York : A. S. Barnes, [1963]