Columbia subject headings:
Income tax--United States.
Intergovernmental fiscal relations--United States.
Social security--United States.
Tax incidence--United States.
Taxation--United States.
Harvard subject headings:
Income tax--United States.
Intergovernmental fiscal relations--United States.
Social security--United States
Tax incidence--United States.
Taxation--United States
Princeton subject headings:
Income tax--United States.
Intergovernmental fiscal relations--United States.
Social security--United States.
Tax incidence--United States.
Taxation--United States.