Não informado. (1976). Water quality bulletin. World Health Organization, Collaborating Centre on Surface and Ground Water.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Water Quality Bulletin. Ontario, Canada: World Health Organization, Collaborating Centre on Surface and Ground Water, 1976.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Water Quality Bulletin. World Health Organization, Collaborating Centre on Surface and Ground Water, 1976.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.