Columbia subject headings:
Illinois Historical Survey. Library.
Labor unions--Officials and employees--United States--Correspondence.
Walker, John Hunter, 1872-1955.
Harvard subject headings:
Illinois Historical Survey. Library.
Labor unions--United States--Officials and employees--Correspondence.
Walker, John Hunter, 1872-1955.
Princeton subject headings:
Illinois Historical Survey. Library
Labor unions--United States--Officials and employees--Correspondence.
Walker, John Hunter, 1872-1955.