Columbia subject headings:
Harvard subject headings:
Competition--United States
Drugs--Generic substitution--Economic aspects--United States.
Drugs--Research--United States--Costs.
Generic drugs--United States.
Pharmaceutical industry--United States
Princeton subject headings:
Competition--United States.
Drugs--Generic substitution--Economic aspects--United States.
Drugs--Research--United States--Costs.
Pharmaceutical industry--United States.