Vitamin D supplementation in patients with COPD: Twitter discussions on behalf of the University of Toronto Respirology and Sleep Journal Club--Authors' Reply
1 Centre for Primary Care and Public Health and Asthma UK Centre for Applied Research, Queen Mary University of London, London E1 2AB, UK. Electronic address: a.martineau@qmul.ac.uk.
2 Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AB, UK.