Columbia subject headings:
Coal miners--Diseases--United States.
Coal mines and mining--Taxation--Law and legislation--United States.
Disability insurance--Law and legislation--United States.
Lungs--Dust diseases.
Harvard subject headings:
Princeton subject headings:
Coal miners--Diseases--United States.
Coal mines and mining--Taxation--Law and legislation--United States.
Disability insurance--Law and legislation--United States.
Lungs--Dust diseases.