G. Miehe and S. Miehe, “Comparative high mountain research on the treeline ecotone under human impact Carl Troll’s Asymmetrical Zonation of the Humid Vegetation Types of the World of 1948 reconsidered: Carl Troll’s ‘Asymmetrical Zonation of the Humid Vegetation Types of the World’ of 1948 reconsidered”, ERDKUNDE, vol. 54, no. 1, pp. 34–50, Mar. 2000.