PĂ©ron, J
Roy, P
Ding, K
Parulekar, W R
Roche, L
Buyse, M
Article History
Received: 7 November 2014
Revised: 31 December 2014
Accepted: 12 January 2015
First Online: 17 February 2015
Competing interests
: The authors declare no conflict of interest.