1. Klärschlammverordnung (1992) Bundesgesetzblatt, part I, pp 912
2. Steinwandter H (1992) Development of micro extraction methods. In: Cairns T, Sherma J (eds) Modern methods of pesticide analysis, Vol 1. CRC Press, Boca Raton, Florida, pp 3
3. Steinwandter H (1985) Fresenius Z Anal Chem 321:600
4. Lamparski LL, Nestrik TJ, Stehl RH (1979) Anal Chem 51:1453
5. DIN (1983) DIN 38414, part 7. Beuth, Berlin