Andreev, Katerina
Denis Iulian Trufa, I
Siegemund, Raphaela
Rieker, Ralf
Hartmann, Arndt
Schmidt, Joachim
Sirbu, Horia
Finotto, Susetta
Article History
Revised: 6 May 2015
Accepted: 4 June 2015
First Online: 8 September 2015
Change Date: 15 September 2015
Change Type: Update
Change Details: This paper was modified 12 months after initial publication to switch to Creative Commons licence terms, as noted at publication
Competing interests
: The authors declared no conflict of interest.