Nielsen R, Johannessen A, Benediktsdottir B, Gislason T, Buist AS, Gulsvik A, Sullivan SD, Lee TA. Present and future costs of COPD in Iceland and Norway: results from the BOLD study. Eur Respir J. 2009 Oct;34(4):850-7. doi: 10.1183/09031936.00166108. Epu