Columbia subject headings:
Harvard subject headings:
African Americans--Pennsylvania--Philadelphia--History.
Historical markers--Pennsylvania--Philadelphia--Guidebooks.
Philadelphia (Pa.)--Guidebooks.
Philadelphia (Pa.)--History.
Princeton subject headings:
African Americans--Pennsylvania--Philadelphia--History.
African Americans--Travel--Guidebooks.
Blockson, Charles L.--Library.
Guidebooks.
Philadelphia (Pa.)--Guidebooks.