Columbia subject headings:
Anthracite coal--Pennsylvania--Schuylkill County.
Schuylkill County (Pa.)--Economic conditions.
Harvard subject headings:
Anthracite coal--Pennsylvania--Schuylkill County.
Schuylkill County (Pa.)--Economic conditions.
Princeton subject headings:
Anthracite coal--Pennsylvania--Schuylkill County.
Schuylkill County (Pa.)--Economic conditions.