(19) APHA (1989). Standard Methods for Examination of Water and Wastewater (17. vyd.). American Public Health Association, American Water Works Association and Water Pollution Control Federation, Washington D.C.
(19) APHA (1989). Standard Methods for Examination of Water and Wastewater (17. vyd.). American Public Health Association, American Water Works Association and Water Pollution Control Federation, Washington D.C.