High altitudes and partial pressure of arterial oxygen in patients with chronic obstructive pulmonary disease - A systematic review and meta-analysis A. Sevik; T. Gaisl; A. Forrer; L. Graf; S. Ulrich; K.E. Bloch; M. Lichtblau; M. Furian;

Impact of acute exacerbations of COPD on patients' health status beyond pulmonary function: A scoping review A. Machado; M. Barusso; J. De Brandt; K. Quadflieg; S. Haesevoets; M. Daenen; M. Thomeer; D. Ruttens; A. Marques; C. Burtin;

Association of mild chronic obstructive pulmonary disease with all-cause mortality: A systematic review and meta-analysis Weifeng Zou; Jie Ou; Fan Wu; Huanuan Fan; Yuyan Hou; Haiqing Li; Zhishan Deng; Shuling Liu; Jinxing Hu; Pixin Ran;