Columbia subject headings:
Aeronautics, Commercial--United States--Employees.
Arbitration, Industrial--United States.
Railroads--United States--Employees.
Harvard subject headings:
Aeronautics, Commercial--United States--Employees.
Arbitration, Industrial--United States
Railroads--United States--Employees
Princeton subject headings:
Aeronautics, Commercial--United States--Employees.
Arbitration, Industrial--United States.
Railroads--United States--Employees.