Promsarn , Simaporn, and Watcharaporn Butrakhum. 2021. “6-Minute Walk Test (6MWT) During the Coronavirus Disease 2019 (COVID-19)”. Siriraj Medical Bulletin 14 (1):57-63. https://he02.tci-thaijo.org/index.php/simedbull/article/view/244465.