Columbia subject headings:
Medical care--Utilization--United States.
Medical economics--United States.
Physician and patient--United States.
Physicians--United States.
Harvard subject headings:
Medical care--Utilization--United States.
Medical economics--United States.
Physician and patient--United States
Physicians--United States
Princeton subject headings:
Medical care--United States--Utilization.
Medical economics--United States.
Physician and patient--United States.
Physicians--United States.