RT Journal Article SR Electronic T1 Facemasks do not lead to abnormal gas exchange during treadmill exercise testing in children JF ERJ Open Research JO erjor FD European Respiratory Society SP 00613-2021 DO 10.1183/23120541.00613-2021 A1 Mallet, Maria Christina A1 Hitzler, Michael A1 LurĂ , Marco A1 Kuehni, Claudia E A1 Regamey, Nicolas YR 2021 UL http://openres.ersjournals.com/content/early/2021/12/02/23120541.00613-2021.abstract AB