- Correspondence to Dr Mohsen Sadatsafavi, Centre for Clinical Epidemiology and Evaluation, 7th Floor, 828 West 10th Avenue, Research Pavilion, Vancouver, BC, Canada V5Z 1M9;
- Received July 7, 2015
- Revised November 10, 2015
- Accepted November 25, 2015
- First published January 5, 2016.
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- Data supplement 1 - Online supplement
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