Singh, Gajendra Vikram, Rajendra Prasad, Surya Kant, Santosh Kumar, Narsingh Verma, Ved Prakash, Ajay Kumar Verma, Santosh Kumar, and Arpita Singh. 2014. “Effects of Pulmonary Rehabilitation on Secondary Polycythemia in Stable Chronic Obstructive Pulmonary Disease: A Pilot Study”. International Journal of Clinical and Experimental Physiology 1 (2), 157-60. https://ijcep.org/index.php/ijcep/article/view/95.