1. Stojda, A. and Dojlido, J.: 1983, ?A Study on the Water Quality Index in Poland?, WHO. Wat. Qual. Bull. 8(1), 30?32.
2. Stojda, A., Dojlido, J. and Woyciechowska, J.: 1983, ?Evaluation of Water Quality With The Use Of WQI?, (in Polish), Gospodarka Wodna 10.
3. Dojlido, J., Woyciechowska, J. and Raniszewski J.: 1991, ?Water Quality Index (WQI) For Summarized Evaluation of Water pollution?, Conference IMWM Poland/Pennstate USA: Water Resource Management and Water Pollution Control. Perspectives from Poland and the United States; Warsaw, 23?25 September.
4. Disposition of Ministry Council from 14 December 1987 concerning classification of waters and conditions for wastewaters discharged to waters and soil, and fines for offence against these regulations (in Polish). Dziennik Ustaw No. 42, 1987.
5. Disposition of Minister of Environment from 5 November 1991 concerning classification of waters and conditions for wastewaters discharged to waters or soil, Dziennik Ustaw No. 116, 1991.