Näsholm, T. (1991). Aspects of nitrogen metabolism in Scots pine, Norway spruce and birch as influenced by the availability of nitrogen in pedosphere and atmosphere. Swedish University of Agricultural Sciences, Dept. of Forest Genetics and Plant Physiology.

Näsholm, Torgny. Aspects of Nitrogen Metabolism in Scots Pine, Norway Spruce and Birch as Influenced by the Availability of Nitrogen in Pedosphere and Atmosphere. Umeå: Swedish University of Agricultural Sciences, Dept. of Forest Genetics and Plant Physiology, 1991.

Näsholm, Torgny. Aspects of Nitrogen Metabolism in Scots Pine, Norway Spruce and Birch as Influenced by the Availability of Nitrogen in Pedosphere and Atmosphere. Swedish University of Agricultural Sciences, Dept. of Forest Genetics and Plant Physiology, 1991.