Mr. Vinayak Kurale et al. 2026. TO COMPARE THE EFFICACY OF BUTEYKO BREATHING EXERCISE AND 90/90 BALL & BALLON BREATHING EXERCISE IN PATIENTS WITH STAGE 1 AND STAGE 2 CHRONIC OBSTRUCTIVE PULMONARY DISEASE. Journal of Population Therapeutics and Clinical Pharmacology. 33, 1 (Jan. 2026), 558–568. DOI:https://doi.org/10.53555/gt22qp49.