1. Nitrate and Nitrites in Drinking Waters Background Document for Development of WHO Guidelines for Drinking-Water Quality,2016
2. Guideline for Drinking Water Quality,2011
3. Council Directive 98/83/EC of 3 November 1998 on the Quality of Water Intended for Human Consumption,1998
4. National Drinking Water Regulation,2009
5. Drinking Water Quality Standards in Japan,2015