Hakala, T. K.
Rekola, H. T.
Väkeväinen, A. I.
Martikainen, J.-P.
Nečada, M.
Moilanen, A. J.
Törmä, P.
Article History
Received: 14 April 2016
Accepted: 25 October 2016
First Online: 3 January 2017
Competing interests
: The authors declare no competing financial interests.