Columbia subject headings:
Professional associations--Canada--Directories.
Professional associations--United States--Directories.
Trade associations--Canada--Directories.
Trade associations--United States--Directories.
Harvard subject headings:
Professional associations--Canada--Directories.
Professional associations--United States--Directories.
Trade associations--Canada--Directories.
Trade associations--United States--Directories.
Princeton subject headings:
Directories.
Professional associations--Canada--Directories.
Professional associations--United States--Directories.
Trade associations--Canada--Directories.
Trade associations--United States--Directories.