Devereux, G., Cotton, S., Fielding, S., McMeekin, N., Barnes, P. J., Briggs, A., Burns, G., Chaudhuri, R., Chrystyn, H., Davies, L., De Soyza, A., Gompertz, S., Haughney, J., Innes, K., Kaniewska, J., Lee, A., Morice, A., Norrie, J., Sullivan, A., Wilson, A., & Price, D. (2018). Effect of Theophylline as Adjunct to Inhaled Corticosteroids on Exacerbations in Patients with COPD: A Randomized Clinical Trial. Journal of the American Medical Association, 320(15), 1548-1559. https://doi.org/10.1001/jama.2018.14432