1. Pulmonology Department, Serdang Hospital, Ministry of Health Malaysia, Selangor, Malaysia
2. Division of Respiratory Medicine, Department of Internal Medicine, Sarawak General Hospital, Ministry of Health Malaysia, Sarawak, Malaysia
3. Division of Respiratory Medicine, Department of Internal Medicine, University of Malaya Medical Center, Kuala Lumpur, Malaysia
4. Pathology Department, Serdang Hospital, Ministry of Health Malaysia, Selangor, Malaysia