Columbia subject headings:
Elections--Equipment and supplies--Purchasing--United States.
Elections--United States--Equipment and supplies--Purchasing.
Voting-machines--Purchasing--United States.
Harvard subject headings:
Elections--Equipment and supplies--Purchasing--United States.
Voting-machines--Purchasing--United States.
Princeton subject headings:
Elections--Equipment and supplies--Purchasing--United States.
Voting-machines--Purchasing--United States.