© 2017 Svenn-Erik Mamelund, Bjørn Haneberg & Siri Mjaaland.
This open-access work is published under the terms of the Creative Commons
Attribution NonCommercial License 2.0 Germany, which permits use,
reproduction & distribution in  any medium for non-commercial purposes,
provided the original author(s) and source are given credit.
See http:// creativecommons.org/licenses/by-nc/2.0/de
Med mindre annet er angitt, så er denne innførselen lisensiert som © 2017 Svenn-Erik Mamelund, Bjørn Haneberg & Siri Mjaaland. This open-access work is published under the terms of the Creative Commons Attribution NonCommercial License 2.0 Germany, which permits use, reproduction & distribution in any medium for non-commercial purposes, provided the original author(s) and source are given credit. See http:// creativecommons.org/licenses/by-nc/2.0/de