1. Arvola L (1984) Vertical distribution of primary production and phytoplankton in two small lakes with different humic concentration. Holarct Ecol 7: 390–398
2. Azam F, Fenchel T, Field JG, Gray JS, Meyer-Reil LA, Thingstad F (1983) The ecological role of water-column microbes in the sea. Mar Ecol Prog Ser 10: 257–263
3. Beijerinck MW (1890) Kulturversuche mit Zoochlorellen, Lichenogonidien and anderen Algen. Bot Ztg 48:725–739, 741–754, 757–768, 781–785
4. Blomqvist P, Heyman U, Grundström R (1981) The structure of the pelagic ecosystem in L. Siggeforasjön. Scr Limnol Ups Coll 18, Scr A22
5. Blomqvist P, Pettersson A, Hyenstrand P (1994) Ammonium-nitrogen: a key regulatory factor causing dominance of non-nitrogen fixing cyanobacteria in aquatic systems. Arch Hydrobiol 132: 141–164