S., Mathanraj, Vysak Kumar, Yuvarajan S., and Vikram Reddy. 2017. “Correlation of Serum TNF Alpha Level With Severity of Chronic Obstructive Pulmonary Disease”. International Journal of Research in Medical Sciences 5 (8):3309-16. https://doi.org/10.18203/2320-6012.ijrms20173020.