- Correspondence to Dr Rob McConnell, Department of Preventive Medicine, Keck School of Medicine of the University of Southern California, 2001 N. Soto Street, MC 9234, Los Angeles, CA 90089, USA;
- Received December 21, 2012
- Revised October 21, 2013
- Accepted October 24, 2013
- First published November 19, 2013.
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