1. GB 11906-89, Potassium periodate spectrophotometric method,1989
2. GB 8978-1996, Integrated wastewater discharge standard,1996
3. HJ/T 20-1998, Technical specifications on sampling and sample preparation from industry solid waste,1998
4. HJ/T 299-2007, Sulphuric acid & nitric acid method,2007
5. NYT1377-2007, Determination of pH in soil,2007