APA
Coal Mines Committee P., Coal Mines Committee P., . (1949). Third session. : .
Chicago
Coal Mines Committee Pitsburg, Coal Mines Committee Pitsburg, . 1949. Third session. : .
Harvard
Coal Mines Committee P., Coal Mines Committee P., . (1949). Third session. : .
MLA
Coal Mines Committee Pitsburg, Coal Mines Committee Pitsburg, . Third session. : . 1949.
