Koitzsch, A.
Heming, N.
Knupfer, M.
Büchner, B.
Portnichenko, P. Y.
Dukhnenko, A. V
Shitsevalova, N. Y.
Filipov, V. B.
Lev, L. L.
Strocov, V. N.
Ollivier, J.
Inosov, D. S.
Article History
Received: 12 October 2015
Accepted: 28 January 2016
First Online: 15 March 2016
Competing interests
: The authors declare no competing financial interests.