References
- Anon., 1973: Unified Research Methods on Water Quality. — Moscow, 376 pp. (in Russian).
- Anon., 1981: Hydrobiological Regime of Small Rivers under Anthropogenic Impact. — Rìga, Zinâtne: 1–166. (in Russian).
- Anon., 1990: Ecological Background Monitoring in Latvia. — Vieda: 1–29 (in Russian).
- APHA, 1992: Standard Methods for the Examination of Water and Wastewater. — Ed. American Public Health Association, Washington, DC. 1026 pp.
- Cimdinš, P., 1995: River typology and parameters for evaluation of their ecological state. — Proceedings of the Latvian Academy of Sciences 95(1/2): 34–48.
- Shannon, C. E. & Weaver, W., 1949: The Mathematical Theory of Communication. — University of Illinois Press, Urbana, 89 pp.
- Slacecek, V., 1979: Continental systems for the assessment of river water quality. — In: Evison, J. A. (ed.): Biological Indicators of Water Quality: 1–32.
- Uhlmann, D., 1982: Hydrobiologie. — VEB Gustav Fischer Verlag, Jena, 315 pp.