Department of Respiratory Medicine, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
Correspondence to Professor Ashok Shah, Department of Respiratory Medicine, Vallabhbhai Patel Chest Institute, University of Delhi, PO Box 2101, Delhi 110 007, India fax: +91 11 27667420; e-mail: [email protected]
doi: 10.1097/MCP.0b013e328011a284