Columbia subject headings:
Lobbying.
Political action committees.
Political campaigns.
Pressure groups--Europe.
Pressure groups--United States.
Harvard subject headings:
Lobbying--Congresses.
Lobbying.
Political action committees--Congresses.
Political action committees.
Political campaigns--Congresses.
Political campaigns.
Pressure groups--Europe--Congresses.
Pressure groups--Europe.
Pressure groups--United States
Pressure groups--United States--Congresses.
Princeton subject headings:
Lobbying.
Political action committees.
Political campaigns.
Pressure groups--Europe.
Pressure groups--United States.