Prevention of exacerbation in patients with moderate-to-very severe COPD with the intent to modulate respiratory microbiome: a pilot prospective, multi-center, randomized controlle... oleh Jian-lan Hua, Zi-feng Yang, Qi-jian Cheng, Yao-pin Han, Zheng-tu Li, Ran-ran Dai, Bin-feng He, Yi-xing Wu, Jing Zhang, Jing Zhang