Idiopathic pulmonary fibrosis - A composite physiologic index derived from disease extent observed by computed tomography - Wells,AU; Desai,SR; Rubens,MB; Goh,NSL; Cramer,D; Nicholson,AG; Colby,TV; du,Bois RM; Hansell,DM (AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE, 2003)