3Viegi G, Seognamiglio A, Baldicci S. Epidemiology of chronic obstructive pulmonary disease (COPD). Respiration, 2001, 68:4 - 19.
4Wouters EF. Economic analysis of the confronting COPD survey: an overview of results. Respir Med, 2003, 97(suppl c):3 - 14.
5Pauwals RA, Buist AS, Calverhy PM, et al. Global strategy for the diagnosis, Management and prevention of chronic obstructive pulmonary disease: NHLBI/WHO Global initiative for chronic obstructive lung disease (GOLD)workshop summary[J]. Am J Respir Crit Care Med, 2001, 163 : 1256 - 1276.