1. US Environmental Protection Agency
, Drinking Water Health Advisory: Pesticides, Lewis, Chelsea, MI, 1989
2. Code of Federal Regulations, US Government Printing Office, Rev., 2001
3. European Union, EEC Drinking Water Guidelines 80/779/EEC, EU, Brussels, 1980
4. US Environmental Protection Agency (EPA), Determination of Diquat and Paraquat in Drinking Water by Liquid-solid extraction and high performance liquid chromatography with ultraviolet detection, 1997
5. Molluscicidal activity of crude water and hexane extracts of Hypericum species to snails (Radix peregra)