Study of oxidative stress biomarkers in chronic obstructive pulmonary disease and their correlation with disease severity in north Indian population cohort. - Bajpai, Jyoti; Prakash, Ved; Kant, Surya; Verma, Ajay Kumar; Srivastava, Anand; Bajaj, Darshan K.; Ahmad, M. K.; Agarwal, Avinash (Lung India, 2017)