1. Department of Pulmonary & Critical Care Medicine, Pandit Bhagwat Dayal Sharma Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
2. Department of Labour, Industrial Health, Rohtak, Haryana, India
3. ESI Health Care Hospital, Faridabad, Haryana, India
4. Civil Hospital Gurugram, Gurugram, Haryana, India