Columbia subject headings:
Medical appointments and schedules--United States--Mathematical models.
Medical fees--United States--Mathematical models.
Physician services utilization--United States--Mathematical models.
Telephone surveys--United States.
Harvard subject headings:
Medical appointments and schedules--United States--Mathematical models.
Medical fees--United States--Mathematical models.
Physician services utilization--United States--Mathematical models.
Telephone surveys--United States.
Princeton subject headings: