Clark, Michael, Angela M. Gurnell, Edward J. Milton, Matti Seppälä, and Maarit Kyöstilä. 1985. “Remotely-Sensed Vegetation Classification As a Snow Depth Indicator for Hydrological Analysis in Sub-Arctic Finland”. Fennia - International Journal of Geography 163 (2):195-216. https://fennia.journal.fi/article/view/9060.