H. BOHLIG, L.J. BRISTOL, P.H. CARTIER, B. FELSON, J.C. GILSON, T.R. GRAINGER, G. JACOBSON, R. KIVILUOTO, J.C. MCDONALD, E.P. PENDERGRASS, C.E. ROSSITER, I.J. SELIKOFF, G.K. SLUIS-CREMER. (1969). UICC/Cincinnati classification of radiographic appearances of pneumoconiosis