Apnoea-hypopnoea-index comparing the 2007 and 2012 American Academy of Sleep Medicine criteria in chronic obstructive pulmonary disease/obstructive sleep apnoea overlap syndrome - He, Baiting; Al-Sherif, Miral; Wu, Yingxin; Higgins, Sean; Schwarz, Esther Irene; Luo, Yuanming; Said, Azza Farag; Refat, Nezar; Abdel Wahab, Nashwa Hassan; Steier, Joerg (Journal of Thoracic Disease, 2020)