1. Blosczyk G (1979) Dissertation Würzburg
2. Brieskorn CH (1984) Ber Physico-Mecdica (Würzburg) 88: im Druck
3. Hull HM (1970) Residue Reviews 31:1
4. Linskens HF, Heinen W, Stoffers AL (1965) Residue Reviews 8:136
5. Crosby DG (1969) Residue Reviews 25:1