Varalakshmi, D. ., M. . .K, and P. . Sumalatha. “EFFECT OF UPPER-LIMB AND THORACIC MUSCLE STRENGTH ON 6-MIN WALK DISTANCE IN COPD PATIENTS”. International Journal of Physiotherapy, vol. 1, no. 2, June 2014, pp. 54-57, https://www.ijphy.com/index.php/journal/article/view/14.