"History and epidemiology of coalworkers' pneumoconiosis. "; "Lapp, N. LeRoy."; "Coal miners--Diseases--Epidemiology.", "Lungs--Diseases.", "Coal miners--Diseases--History.", "Pneumoconiosis--History.", "Pneumoconiosis--Epidemiology."; "Lapp, N. LeRoy."; "1969"; "Journal article reprint from: The Virginia Medical Monthly, v.96 (1969:Dec.). "; ""; "P16589"; "pec"; "Pneumoconiosis--Epidemiology.", "Pneumoconiosis--History.", "Coal miners--Diseases--History.", "Coal miners--Diseases--Epidemiology.", "Lungs--Diseases."; "14256"; .