Citation - Babu AS, Arena R, Myers J, Padmakumar R, Maiya AG, Cahalin LP, Waxman AB, Lavie CJ. Exercise intolerance in pulmonary hypertension: mechanism, evaluation and clinical implications. Expert Rev Respir Med. 2016 Sep;10(9):979-90. doi: 10.1080/17476348.2016.1191353. PubMed PMID: 27192047.