- Correspondence to Dr André F S Amaral, Respiratory Epidemiology, Occupational Medicine and Public Health, National Heart and Lung Institute, Imperial College London, Emmanuel Kaye Building, 1B Manresa Road, London SW3 6LR (UK);
- Received September 25, 2013
- Revised February 11, 2014
- Accepted February 13, 2014
- First published March 10, 2014.
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