Smith, B., Traboulsi, H., Austin, J., Manichaikul, A., Hoffman, E., Bleecker, E., … SPIROMICS, investigators. M. L. and. (2018). Human airway branch variation and chronic obstructive pulmonary disease. Proceedings of the National Academy of Sciences of the United States of America. https://doi.org/10.1073/pnas.1715564115 (Original work published 2018)

Rutten, E., Spruit, M., McDonald, M., Rennard, S., Agusti, A., Celli, B., … ECLIPSE, I. (2015). Continuous fat-free mass decline in COPD: fact or fiction? The European Respiratory Journal, 46(5), 1496-8. https://doi.org/10.1183/13993003.00692-2015