1. International Labour Office Guidelines for the use of the ILO classification of radiographs of pneumoconiosis Occupational Health Series No. 22 (Rev 80) 1980 Geneva
2. Normal chest roentgenograms in chronic diffuse infiltrative disease;Epler;N Engl J Med,1978
3. Diagnosis of diseases of the chest;Fraser,1977
4. Radiological features of asbestosis;Solomon,1989
5. Radiographic features of coal workers' pneumoconiosis;Morgan,1989