1. Lung Changes in Ankylosing Spondylitis
A.K. Sil, M.B.B.S. 
CHEST 
Volume 61, Issue 4, Pages (April 1972)
DOI: /chest
Copyright © 1972 The American College of Chest Physicians Terms and Conditions

2. Figure 1 Small opacity in left apex.
CHEST  , DOI: ( /chest )
Copyright © 1972 The American College of Chest Physicians Terms and Conditions

3. Figure 2 Increased opacity, left apex.
CHEST  , DOI: ( /chest )
Copyright © 1972 The American College of Chest Physicians Terms and Conditions

4. Figure 3
Further increase in opacity, left upper zone, with development of cyst formation.
CHEST  , DOI: ( /chest )
Copyright © 1972 The American College of Chest Physicians Terms and Conditions