Columbia subject headings:
Mineral industries--Russia (Federation)--Ural Mountains Region--History--20th century.
Working class--Russia (Federation)--Ural Mountains Region--History--20th century.
Harvard subject headings:
Mineral industries--Russia (Federation)--Ural Mountains Region--History--20th century.
Working class--Russia (Federation)--Ural Mountains Region--History--20th century.
Princeton subject headings:
Mineral industries--Russia (Federation)--Ural Mountains Region--History.
Working class--Russia (Federation)--Ural Mountains Region--History.