1. Steinwandter H (1985) Fresenius Z Anal Chem 522:752
2. Steinwandter H (1988) Universal extraction and cleanup methods. In: Sherma J (ed) Analytical methods for pesticides and plant growth regulators, vol XVII, p 35. Academic Press, Orlando, Florida
3. Steinwandter H (1989) Universal extraction methods for the determination of organic residues — beginning and evolution —. Lecture presented on the VDLUFA Kongre\ in Bonn. In: (Association of german agricultural experiments and research stations (eds) Kongre\band Bonn. VDLUFA-Schriftenreihe, part II, 28:1069, VDLUFA-Verlag, Darmstadt (in press)
4. Goodwin ES, Goulden R, Reynolds JG (1961) Analyst 86:697
5. Becker G (1971) Dtsch Lebensm Rundsch 67:125