United States Employment Service & United States Employment Service. (1979). Conversion table of code and title changes, third to fourth edition, Dictionary of occupational titles. The Service : for sale by the Supt. of Docs., U.S. Govt. Print. Off.
Chicago-referens (17:e uppl.)United States Employment Service och United States Employment Service. Conversion Table of Code and Title Changes, Third to Fourth Edition, Dictionary of Occupational Titles. Washington: The Service : for sale by the Supt. of Docs., U.S. Govt. Print. Off, 1979.
MLA-referens (9:e uppl.)United States Employment Service och United States Employment Service. Conversion Table of Code and Title Changes, Third to Fourth Edition, Dictionary of Occupational Titles. The Service : for sale by the Supt. of Docs., U.S. Govt. Print. Off, 1979.