Kujala, S T
Knürr, T
Kärkkäinen, K
Neale, D B
Sillanpää, M J
Savolainen, O
Article History
Received: 30 March 2016
Revised: 30 August 2016
Accepted: 11 October 2016
First Online: 30 November 2016
Competing interests
: The authors declare no conflict of interest.