1. Bell, W. H., Lang, J. M. & Mitchell, R., 1974. Selective stimulation of marine bacteria by algal extracellular products. Limnol. Oceanogr. 19: 833–839.
2. Broberg, O. & Persson, G., 1981. Närsalttillgång i försurade sjöar. Fosfor, kväve och organiskt kol i Gårdsjön. Rep. Limnol. Inst., Univ. Upps. 55 pp.
3. Coveney, M. F., Cronberg, G., Enell, M., Larsson, K. & Olofsson, L., 1977. Phytoplankton, zooplankton and bacteria — standing crop and production relationships in an eutrophic lake. Oikos 29: 5–21.
4. Grahn, O., Hultberg, H. & Landner, L., 1974. Oligotrophication — a self-accelerating process in lakes subjected to excessive supply of acid substances. Ambio 3: 93–94.
5. Grahn, O. & Lydén, A., in prep. Primary producers and production in lake Gårdsjön.