1. Royal Ministry for Foreign Affairs and Royal Ministry of Agriculture, 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, 96 pp. (1971).
2. N. Malmer, Om effekterna på vatten, mark och vegetation av ökad svaveltillförsel från atmosfären. En översikt från ekologiska utgångspunkter. (On the effects of water, soil and vegetation from an increasing atmospheric supply of sulfur. A survey on ecological bases.) Statens Naturvårdsverk, Solna. SNV PM 402: 125 pp. (1973).
3. C. O. Tamm, Acid precipitation: Biological effects in soil and on forest vegetation, Ambio 5: 235 (1976).
4. C. O. Tamm, G. Wiklander, and B. Popovic, Effects of application of acid to poor pine forest, Water, Air, and Soil Pollution 8: 75 (1977).
5. G. Abrahamsen, K. Bjor, and 0. Teigen, Field experiments with simulated acid rain in forest ecosystems. SNSF-prosjektet FR 4/76, 0slo-Ås, 15 pp. (1976).