Zhao, Xiang http://orcid.org/0000-0003-1054-9462
Davey, Gareth
Article History
Received: 7 March 2017
Accepted: 6 June 2017
First Online: 17 June 2017
Compliance with ethical standards
: The study was approved by the appropriate institutional ethics procedures, and individual participants gave informed consent. It was performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments.
: The authors declare that they have no conflict of interest.
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