Columbia subject headings:
Air quality--Ouachita Mountains (Ark. and Okla.)
Air quality--Ozark Mountains Region.
Forests and forestry--Ouachita Mountains (Ark. and Okla.)
Forests and forestry--Ozark Mountains Region.
Ouachita Mountains (Ark. and Okla.)--Economic conditions.
Ouachita Mountains (Ark. and Okla.)--Social history.
Ozark Mountains Region--Economic conditions.
Ozark Mountains Region--Social history.
Water quality--Ouachita Mountains (Ark. and Okla.)
Water quality--Ozark Mountains Region.
Harvard subject headings:
Air quality--Ouachita Mountains (Ark. and Okla.)
Air quality--Ozark Mountains Region.
Forests and forestry--Ouachita Mountains (Ark. and Okla.)
Forests and forestry--Ozark Mountains Region.
Ouachita Mountains (Ark. and Okla.)--Economic conditions.
Ouachita Mountains (Ark. and Okla.)--Social conditions.
Ozark Mountains Region--Economic conditions.
Ozark Mountains Region--Social conditions.
Water quality--Ouachita Mountains (Ark. and Okla.)
Water quality--Ozark Mountains Region.
Princeton subject headings: