Circumpolar Arctic vegetation: a hierarchic review and roadmap toward an internationally consistent approach to survey, archive and classify tundra plot data oleh D A Walker, F J A Daniëls, I Alsos, U S Bhatt, A L Breen, M Buchhorn, H Bültmann, L A Druckenmiller, M E Edwards, D Ehrich, H E Epstein, W A Gould, R A Ims, H Meltofte, M K Raynolds, J Sibik, S S Talbot, P J Webber