Hu, S.
Lozada-Hidalgo, M.
Wang, F. C.
Mishchenko, A.
Schedin, F.
Nair, R. R.
Hill, E. W.
Boukhvalov, D. W.
Katsnelson, M. I.
Dryfe, R. A. W.
Grigorieva, I. V.
Wu, H. A.
Geim, A. K.
Article History
Received: 25 August 2014
Accepted: 23 October 2014
First Online: 26 November 2014
Competing interests
: The authors declare no competing financial interests.