Bronchodilator responsiveness as a phenotypic characteristic of established chronic obstructive pulmonary disease
Albert, P., Agusti, A., Edwards, L., Tal-Singer, R., Yates, J., Bakke, P., Celli, B. R., Coxson, H. O., Crim, C., Lomas, D. A., MacNee, W., Miller, B., Rennard, S., Silverman, E. K., Vestbo, J., Wouters, E., Calverley, P.