Okamura, Y.
Kagawa, F. http://orcid.org/0000-0002-1763-6799
Seki, S. http://orcid.org/0000-0001-6094-8643
Tokura, Y.
Article History
Received: 22 March 2016
Accepted: 20 July 2016
First Online: 1 September 2016
Competing interests
: The authors declare no competing financial interests.