Columbia subject headings:
Business consultants--Directories.
Business consultants--United States--Directories.
Marketing research--Directories.
Marketing research--United States--Directories.
Harvard subject headings:
Business consultants--Directories.
Business consultants--United States--Directories.
Marketing research--Directories.
Marketing research--United States--Directories.
Princeton subject headings:
Business consultants--Directories.
Business consultants--United States--Directories.
Directories.
Marketing research--Directories.
Marketing research--United States--Directories.