Autio, J., O. Heikkinen, L. Koutaniemi, A. Colpaert, and S. Luoma-Aho. “Physical Geography at the University of Oulu: Research in Finland and Adjacent Areas”. Fennia - International Journal of Geography, vol. 172, no. 2, Feb. 1994, pp. 163-71, https://fennia.journal.fi/article/view/8901.