1.NBN T 91-201 Determination of the chemical oxygen demand。 2.ISBN O 11 7512494 Chemical oxygen demand(dichromate vaLue)of polluted and waste waters。 3.NF T 90-101 Determination of the chemical oxygen demand。 4.DIN 38409-H-41 Determination of the chemical oxygen demand(COD)within the range above 15mg per Litre。 5.NEN 3235 5.3 Bepaling van het chemisch zuurstofverbruik。 6.ISO 6060 Water quality:chemical oxygen demand dichromate methods。