1. Lumb AB: Airways disease; in Nunn's Applied Respiratory Physiology, ed 5. Edinburgh, Butterworth-Heinemann, 2000.
2. West JB: Tests of pulmonary function; in Respiratory Physiology: the Essentials, ed 7. Philadelphia, Lippincott Williams & Wilkins, 2005.
3. Isolated diffusing capacity reduction in systemic sclerosis