Su, Zheng
Zhang, Junjie
Kumar, Chanchal
Molony, Cliona
Lu, Hongchao
Chen, Ronghua
Stone, David J.
Ling, Fei
Liu, Xiao
Article History
Received: 15 March 2016
Accepted: 5 September 2016
First Online: 23 September 2016
Competing interests
: Chanchal Kumar, Cliona Molony, Hongchao Lu, Ronghua Chen and David J. Stone are full time employees in Merck & Co., Inc. The other authors declare that they have no competing interests.