Columbia subject headings:
Agricultural laborers--United States.
Mexicans--United States.
Railroads--United States--Employees.
World War, 1939-1945--Manpower--United States.
Harvard subject headings:
Agricultural laborers--United States
Mexicans--United States
Mexico--Emigration and immigration--Government policy--History--20th century.
Railroads--United States--Employees
United States--Emigration and immigration--Government policy--History--20th century.
World War, 1939-1945--Manpower--United States.
Princeton subject headings:
Agricultural laborers--United States.
Mexicans in the United States.
Mexicans--United States.
Railroads--United States--Employees.
World War, 1939-1945--Manpower--United States.