Erratum: A randomized, seven-day study to assess the efficacy and safety of a glycopyrrolate/formoterol fumarate fixed-dose combination metered dose inhaler using novel Co-Suspension™ Delivery Technology in patients with moderate-to-very severe chronic obstructive pulmonary disease. [Respir Res. 18, 1 (2017), (8)] DOI: 10.1186/s12931-016-0491-8