APA (7th ed.) Citation

N, P., MB, D., JE, C., PD, S., DP, T., NN, H., & RA, W. (2014). Chronic productive cough is associated with death in smokers with early COPD. COPD, 11(4), 451. https://doi.org/10.3109/15412555.2013.837870

Chicago Style (17th ed.) Citation

N, Putcha, Drummond MB, Connett JE, Scanlon PD, Tashkin DP, Hansel NN, and Wise RA. "Chronic Productive Cough Is Associated with Death in Smokers with Early COPD." COPD 11, no. 4 (2014): 451. https://doi.org/10.3109/15412555.2013.837870.

MLA (9th ed.) Citation

N, Putcha, et al. "Chronic Productive Cough Is Associated with Death in Smokers with Early COPD." COPD, vol. 11, no. 4, 2014, p. 451, https://doi.org/10.3109/15412555.2013.837870.