Martikainen, Miika
Ruotsalainen, Janne
Tuomela, Johanna
Härkönen, Pirkko
Essand, Magnus
Heikkilä, Jari
Hinkkanen, Ari
Article History
Revised: 12 April 2017
Accepted: 2 May 2017
First Online: 30 May 2017
Competing interests
: The authors declare no conflict of interest.