1. Bowker, D. W. & P. Denny, 1980. The seasonal succession and distribution of epiphytic algae in the phyllosphere of Lemna minor L. Hydrobiologia 90: 39?55.
2. Cohen, Y., B. B. Jorgensen, N. P. Revsbech & R. Poplawski, 1986. Adaptation to hydrogen sulfide of oxygenic and anoxygenic photosynthesis among cyanobacteria. Appl. envir. Microbiol. 51: 398?407.
3. Duffield, A. N., 1981. The impact of Lemna on the oxygen resources of channels of potential value as fisheries. Proc. Aquat. Weeds Contr.: 257?264.
4. Germain, H. 1981. Flore des Diatomées, Eaux douces et saumatres. Boubée, Paris, 444 pp.
5. Goldsborough, L. G. & G. G. C. Robinson, 1983. The effect of two triazine herbicides on the productivity of freshwater marsh periphyton. Aquat. Toxicol. 4: 95?112.