Pradeep Nirala, Rajeev Tandon, and Mohit Bhatia. “A Study on Biomass Exposure-Associated Chronic Obstructive Pulmonary Disease Among the Patients Visited at a Tertiary Care Hospital”. International Journal of Health and Clinical Research, vol. 4, no. 14, Aug. 2021, pp. 395-7, https://ijhcr.com/index.php/ijhcr/article/view/4556.