© The Author(s) 2015. This is on open access article distributed under the terms of the Creative Commons Attribution 3.0 License which permits any use, reproduction and distribution of the work without further
permission provided the original work is attributed as specified on the SAGE and Open Access page (http://www.uk.sagepub.com/aboutus/openaccess.htm).
Ellei muuten mainita, aineiston lisenssi on © The Author(s) 2015. This is on open access article distributed under the terms of the Creative Commons Attribution 3.0 License which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (http://www.uk.sagepub.com/aboutus/openaccess.htm).