Columbia subject headings:
Firearms--Law and legislation--United States--Handbooks, manuals, etc.
Gun control--United States--Handbooks, manuals, etc.
Harvard subject headings:
Firearms--Law and legislation--United States--Handbooks, manuals, etc.
Gun control--United States--Handbooks, manuals, etc.
Princeton subject headings:
Firearms--Law and legislation--United States--Handbooks, manuals, etc.
Gun control--United States--Handbooks, manuals, etc.