1. Arovaara, H., Hari, P. and Kuusela, K.: 1984, Commun. Inst. For. Fenn. 122, 1.
2. Abrahamsen, C.: 1980, ?Acid precipitation, plant nutrients and forest growth?. In: Drabløs, D, & Tollan, A. (eds) Ecological impact of acid precipitation. Proc. of an Int. Conf. Sandefjord, Norway, March 11-14, 1980, 58?63. SNSF-project, Ås, Norway.
3. Aronsson, A.: 1985, ?Trädens växtnäringstillstånd i områden med skogsskador?. (?Nutritional status of trees in areas with forest decline?). In: Skogsfakta Konferens 8. Uppsala. Sweden
4. Anonymous: 1972, Air pollution across national boundaries. The impact on the environment of sulfur in air and precipitation. Sweden's case study for the United Nations conference on the human environment. Stockholm. Royal Ministry for Foreign Affairs.
5. Anonymous: 1982, Acidification ? today and tomorrow. A Swedish study prepared for the 1982 Stockholm Conference on the Acidification of the Environment. Ministry of Agriculture. Stockholm.